The amount of shill accounts I've seen asking for donations today in Alternate cryptocurrencies for one altcoin alone has been amazing.
For all those giveaway (bitcoin / altcoins / gambling credits / whatever), the organizers should really set a minimum activity requirement (say, 29 activity / at least 4 weeks old account) .
It would not solve the problem, but it will reduce the problem significantly IMHO.
I agree that this could be the best solution. all these 20 accounts stuff are just at 3-5 activity usually and that solution could be effective.
The really funny thing is if you look into satoshicircle giveaway in games and rounds more than %50 of participants are at 5-6 posts and all are in other satoshicircle giveaways (except the first which is in the newbie subforum)