I'd be more than happy to assist you. Leaving your tablet charged is not necessarily a problem if that's going to be the typical application. However keeping a battery charged constantly eventually shortens the lifespan of the battery itself. But that's a moot point if the only reason you have the tablet is to monitor the security cameras and it will always be plugged in anyway.
Other than shortening the lifespan of the actual battery itself, there is no negative consequences to keeping your tablet charged constantly. Additional Reading