The "official" word from Disney security told to one camper is:
one camper, one tent, and an awning and/or screen room.
OR
Two tents, and an awning and/or screen room.
Now having said that,
I've had three tents and 2 EZ-Ups up on a site in 2000.
Not a word was said.
I'm thinking back there where there are mostly tent campers, they don't care as much, but on the main thoroughfare where there are lot's of big rigs, they enforce it a bit more.
Here are pictures