Tablets allowed in a high security environment, that's surprising  

As a software option, you may check this kind of app

https://play.google.com/store/apps/details?id=jp.ne.neko.freewing.DisableCameraDevice

I have no idea how efficient or appropriate it is... may be a problem as the camera CAN be enabled again by software.

I am not expect but here is another suggestion, if you can accept an irreversible operation and you need to do it thru hardware, you can probably disable the cameras by opening the tablet case and disconnecting the two camera modules from the mother board. The cam init will probably just fail at tablet boot but should not cause further problem. Before opening the case, I recommend checking some U30GT2 motherboard pictures to check how the camera are mounted and connected and evaluate the job to be done.

Maybe a low tech option would also be to put some hard glue on top of the camera glass so proper pictures can't be taken.

Cheers.