I chaperoned my DD and friends at disneyworld for a weekend last year. I brought my Nook and sat in "england" in Epcot and read and drank Harp all day. It was actually really pleasant, BUT I did have several people in plain clothes stop by to chat me up throughout the day. They seemed like guests and were very nice, but by the third I recognized it as a script. After I convinced him that I was familiar with the security business he opened up a little.
There are a lot of plain clothes people in the parks. They generally discourage loitering like I was doing. Some are harmless (like me) but most fall into several groups that they have to watch out for like:
ROH criminals--Generally a lookout or a scout sizing up locations. They also act as a drop for merchandise someone else has lifted.
pimps--Yup, the oldest profession is alive and well and apparently themed girls (for those of you with a princess fetish) are available in the World.
pedofiles--He said they don't worry about abductions so much but lots of discreet photo taking. With this group bumping up against people in lines is also a problem. I knew of this tactic. Watch for single guys (sorry but it's mostly men) who wait to join a line until they find the person they want to get behind and then hop on. Usually it's teen or preteen girls. This is very common at water parks on the lines for slides or in wave pools (they purposely wipe out into you).
A new one--furries. I guess if you're a furry fan disneyworld offers a lot of opportunities to satisfy your fetish.
So if that hasn't creeped you out, enjoy your season pass and be prepared to try and explain why you're there :)