A stranger gave me my active about 2 weeks ago and I've been wanting to battle for the last 2 weeks. My question is why the need for the ban? It's not like that on neo.

The ban is put in place to stop people from lending out big pets to other users during events in order to stop the mass inflow of special loot the challengers may drop.

I guess that makes sense .. the ban is only 31 days though, correct?

Because the system was abused to generate more top battle prizes during events. People maxed their wins and loaned/borrowed pets to get more loot. [edit]Too slow!

Actually, I am pretty sure that it is 30 days and not 31. After that, you should be able to battle with a transferred pet. Interestingly enough, there is another limit put in place to stop people from transferring their battle pets: any pet with 2000 or more in any stat will lose 10% of all of their stats of 2000+ when transferred.