First of all, sorry for the delay. It will actually work for developing countries to bring in new members as part of the 0.01 BTC is going to be used as an incentive to the referrer. There are a lot of people out of the Bitcoin scenario in developing countries. We aim to reach them with mutual incentive.
And... there is no average of a scam attempt. The figure u r providing is highly fictitious. Anything that is NOT free is a hindrance to basic scam.
To me, having to pay a figure, even a small figure is off-putting. I guess it isn't so bad with Bitcoin as it is really easy to send payment without having to fill in forms of personal details.
However if I were a scammer, 0.01 BTC sign up fee would not put me off whatsoever. I'd associate it as a cost associated with attempting to scam. If I scammed 1 BTC then my net gains would only be 0.01 BTC less than it would have been in the instance of free entry.
Sure you use the 0.01 BTC to incentivise referrals, but I wouldn't advertise it as a mechanism to greatly reduce scamming, because it really isn't. I read that the Silk Road had a bond of ~4 BTC (it varied according to market value) for sellers, which they received back after a number of successful trades and over a minimum period. Now that's what I call collateral.