If this is not a sale, you should not be involving money in any way in any transaction involving tBTC.
It would probably also be a good idea to tell the people who are posting nonsense that they need xx tBTC instead of 0.00xx tBTC that faucets give out, that there is no reason to need a specific amount of tBTC. Frankly, if you are unable to adjust the code in your application you are testing to account for the difference between 50 tBTC and 0.0005 tBTC, then your application is not ready.
If i wouldn't request COLLATERAL, i wouldn't get anything back... Simple as that... If an established member would ask me to borrow some tBTC for tests, i'd give it to them without collateral, if it's somebody with a throwaway account, i request collateral because, eventough tBTC is WORTHLESS, it's still not FREE to mine tBTC... As a matter of fact, it's quite costly.
A real-world example, i really don't like art... I just don't get it... But, if my daughter makes a clay pot, colors it with those special ceramic (expensive) colors, then bakes it, it has a certain function for her (she decorates her room with them, for example).
The effective net worth of the artwork is $0, but that pot actually cost me $20 in raw materials. Eventough it's worth $0, my daughter still needs it to decorate her room, and if it's gone she'll need to make a new pot, worth $0 but costing $20 in raw materials.
If, one day, somebody bumps in to me in the street, i've never seen the guy, i don't know where he's from, but he asks for my daughter's pot and pinky promises to give it back... I'd request him to pay at least $20 in collateral. If he gives the pot back, he'll get his $20 back... If he runs, at least i have the cost of the raw material and my daughter can use the stranger's $20 to buy new clay, ceramic paint and power for my oven, so she can make a new pot (with an effective worth of $0, but costing $20 in raw materials) to decorate her room.
Same with these tBTC... They're worth $0, but i need to rent hashpower, setup a pool, do a lot of setup work and monitoring to mine them... So the cost to mine them is not $0, they're just worth $0, but their cost is a LOT higher...
As for your second remark... There are tons of things you'd need higher amounts of tBTC for. Sure, you can adjust your code to work with smaller amounts, but you shouldn't need to... Every adjustment you make results in a difference between your tests and your final production code. Also, as a simple example, i've written a mixer in the past, if you're going to create thousands and thousands of tumbling transaction to analyse the taint, you're not going to get very far with 0.0005 tBTC, especially since eacht transaction will cost you about 200 tSat in fees...
I make the assumption that anyone asking for large amounts of testnet coins is a scammer looking to rip someone off who does not understand the diffidence between mainnet and testnet. It's also a somewhat trivial programming change to mask the fact that the reference client is running on testenet. Probably other clients also can be changed somewhat easily not to show that it's on testnet.
But yeah for programming 10=1=.1=.01 should not matter how many coins you have.
And if you are any kind of non scammer you can just rent hashrate be it at nicehash / mining rig rentals / wherever and for a few bucks get them yourself.
If you have a real project it's just the cost of startup.
-Dave
I personally don't think it's that easy to scam somebody with tBTC...
You either have to guide them to a fake wallet that you've compiled yourself to make it look like the testnet is actually the main net, get them to download said wallet and use it. Sure, the reference (non-gui) wallet is easyer to change, but i don't think you'll get any complete novice to run a cli wallet.
Or you have to get them to execute a cli command including --testnet or get them to execute a startup script where you've hidden the --testnet parameter, then convince them everything is normal while the wallet's gui is filled with the word "testnet".
On top of that, if they want to confirm the transaction on any thirth party tracker, you'd have to convince them the fact the tracker clearly says "testnet" is normal for the main net.
I don't say this kind of scam is impossible, i'm just saying that (for a scammer with these kinds of convincing strategies) it would be easyer to let your victim download a completely 100% fake wallet that isn't even on the testnet, and just shows whatever balance you've hardcoded, or whatever balance it gets from your command an controll server... Or, for sheer simplicity, sell them BCH or BCG for the price of BTC. These strategies would be far easyer than procurring tBTC and scamming someone with it.
Case in point: i've seen dozens of people getting scammed with BCH, i've seen people getting scammed by double spending, i've seen people getting scammed with 100% fake wallets... But i've never met somebody that was scammed with tBTC, and i've been around for a while. Once again, it IS possible to scam with tBTC, but there are far easyer methods around (or so it seems).
Personally, i've met situation where i needed vast amounts of tBTC, and i believe other people can run into the same problems... I could turn a blind eye because somebody *might* try to scam (since it's not impossible), but i try to think that people might actually need tBTC for real life tests.
BTW, mining tBTC, especially in vast quantities is NOT that easy as you'd think... The block reward is 0.39 tBTC/block and the diff (last time i checked) was >13M. Next to the high diff and the low block reward, you'd have to setup a full node and setup a pool, or at least find a way to solo mine using rented hashrate using your own node. It's just not that simple. You've quoted PART of my post calculating how much work goes into 1 tBTC, you just snipped the part where the actual calculations took place. Since then the diff has even gone up, so those calculations are an underestimation...