I'll leave the judgement aside, especially since I'm very much on the pro-legalization end of the spectrum.
Pre-hire they likely will, but they maintain the right to test you at any time. Also, in the event of a work related injury, you may be tested. This is pretty much the norm for most employers in the US.
Lastly, do NOT give Disney a reason to suspect you. If your boss smokes, that's wonderful - you don't. Disney leadership can be very backstabby, and if you admit to partaking in front of your boss who also does, it won't matter that they do it to - you fessed up.
And for s sake, do NOT keep anything on property, including any housing which Disney may provide. Do not do this at all. If you do that, you're asking to get termed and arrested.
Saying that, odds are if you're tested, it'll be pre-hire only. Disney rarely does subsequent testing, especially since if they were to test all of their CM's, they'd be unable to remain staffed to the levels they require.
Oh, and don't use drugs... or some like that. Seriously, do whatever you want with your life, just don't ruin someone else's.