After file sharing, if a new iTunes account is added to the device and synced, will the shared files be deleted?

My company would like to give out iPads to contest winners and have company owned "propoganda" loaded onto the iPad for the winners to view. Most likely videos, word documents and possibly more. I have a couple of questions about that.

1. Without building a file sharing app ourselves what apps are the best for file sharing through iTunes?
2. If we load files onto a device using our iTunes Account, then hand it over to the winner and they put their iTunes account on the device and sync it, will the files we pre-loaded be erased?
3. If so, are there any other solutions to accomplish this task?

Thank you for any help you can provide!