There are three companies now offering the free info deal. Two require credit cards and if you read everything carefully they will automatically renew those domains before they expire in one year, unless you advise otherwise in advance. Other than that, I do not see any negatives. The info registrars are doing this promotion for various reasons including # 1 is to get more customers; I personally discovered one registrar of the three that I really like and will be doing more business with them in the .info, .com, etc. Two, they hope that you will try some of their hosting or email services and they will make money, and of course if you renew the domains in a year they will make money.
I think a large number of people registering these free .info domains include email spammers. To them they are just free throw-away domains. Just like the .biz spammers kill the value of those domains, I think these promotions will do the same for .info It makes these domains even less valuable in the long run by tarnishing the image of the TLD.