There are designated smoking areas in Disney world. In all their parks and resorts. Just no selfie sticks. [emoji23][emoji23]
I didn't say there isn't. I said, in different words, it's crowded! I wouldn't presume many places it's not bothering anyone. If you can make it to a less popular park when it's "dead", though, I doubt they'd bother you if you don't flaunt it in front of employees. When I want to just sit back a while and vape, I usually use a designated area, or as close to it as I can stand anyway. There can be a lot of time walking, including through those long mostly-empty line corrals designed for 1000 people. The best reason to vape would also be the worst, bored standing in line, don't do that.
If I were looking for super stealth though, NJoy King maybe?