Letting strangers into your apartment building

[mason55]

I'm a little more interested in people who don't live in dorms, cuz this is pretty common with dorms.

For those of you who live in an apartment building, do you let strangers in when they're waiting? Does the time of day matter? Does their appearance matter? The neighborhood you live in?

I live in a pretty nice area in a very nice building and I almost always let people in if they're waiting. At the same time I feel bad about it. Like if someone else in the building saw me do it they'd be mad at me. I got locked out of the building the other night (we have an intercom with remote door unlock but my roommate was asleep and didn't hear me buzzing) and was sitting out front in a baseball hat and hoodie with my hood up. 2 girls from the building I had never seen before were obviously very reluctant to let me in at 2:30am.

For those that don't let others into the building, what do you do/say? Usually the person waiting just grabs the door behind me, so I'd have to turn around and pull the door shut, seems really awkward.