Technically, yes. However, it is not very plausible. The magnets used in the cover and the iPad itself have a very limited range of influence, and only in direct contact is the magnetic flux any appreciable strength.
What this means is that it is possible, but only if you repeatedly drag your credit cards magnetic strip across the magnets. This is the only way to reliably overcome the magnetic domains, as they are clustered together, making them more resistant to change.
Think of the bed of nails magic trick. The dude can lay on it without pain because the force is distributed equally. the same applies to clustered magnetic information on physical media.
However motel/hotel cards have a different information structure, and much less of it at that, and likely use a cheaper magnetic strip formulation.
In conclusion, just don't use your credit/bank card to pry the cover off!
This question was migrated from http://meta.ifixit.com/.
- de iRobot