Bed bugs are actually very common in movie theaters.
I have also gotten out of movie theater (a shop) and was scratching my legs like crazy. I lifted up my pant legs, and had bites all over my legs. They are common in hotels, libraries. public transit like trains, busses and taxis. They are also found in gyms and locker rooms.
Where ever they are, people "take them home" with them every day. They are very difficult to get rid of. They have even found bed bugs inside the pages of library books. (the ones you check out and take home).