I am not suggesting prohibition. Just tell people plainly that if they are into scams and want to participate in scamming people there are exchanges that specialise in that so go play in those exchanges.
Meanwhile try to find an exchange you can mention to friends without feeling like you are sending them out to get scammed.
In Canada we have CAvirtex which handles only Bitcoin and CAD, that seems maybe a little more conservative than most people here would prefer I expect.
There is also Vault of Satoshi, I guess it is time to see what else they carry besides Bitcoin and CAD, although I have found they are insanely hard to get clearance for since they are doing things like asking for two photo IDs, which no one in Canada even has unless they are globe-trotters thus equipped with a passport.
Though they also are inconsistent with that; after much argument with them over email they now claim a credit card or birth certificate will do as a second ID even though they don't have photos on them.
I have been using Vircurex so far, but when they suddenly listed DOGE that worried me a lot, then the fact they seemingly were not listing DOGE to replace one of the other scrypt coins that has even more pathetic hashrate thus even more vulnerability than DOGE that worried me even more. Are they too going to end up flooded with crap, if only by not dropping the crappiest of the scrypt coins they had when finding a more secure one (higher hashing power) to replace it with?
Any other exchanges that maybe have a few very carefully chosen altcoins instead of letting themselves get lobbied by scammers into adding scamcoins just to make a buck out of fooling the uninformed into buying into blockchains that are not secure and probably never will be secure?
-MarkM-
In fairness to Vircurex, Vircurex typically looks at hash rate to determine inclusion. DOGE had a high hash rate (probably #3 among all scrypt cois).
Is DOGE a good investment. of course not.
So maybe hash rate is not enough... maybe the coin should be around for at least 6 months prior to listing.
Amyway, the responsibility falls on the exchanges to ensure the quality of the coins they trade.
Of course, that doesn't prevent stuff like NXT that create their own exchanges!