It is legal since you are a guest on their property.
Nonetheless, it doesn't bother me one bit for them to check me. When a business loses money due to theft, honest people end up paying more for items.
I remember all of the controverary over wiretaps. If my family can live in a safe place, I'll all for trading some my right of privacy for family security. Of course, I would feel sorry for anyone that would have to listen to my boring phone calls or read my silly emails (cars, blah, blah; girls
, blah, blah; cars, blah; guns...; blah, blah).