I've lived here 33 years and in that time I've had 3 stranger cats who would just come and go as they pleased. My own cats back then tolerated them - one (I still have) treated the last one as a great friend. The only time we had a problem was when a different one came in and sat unseen on the dining room chair - a lot of hissing from one of mine ensued and we finally discovered the intruder - he was black as coal so well hidden. I don't know who was more shocked me, him or the cat who discovered him.
You can get cat flaps which will only open via the micro chip but they have to push harder - neither of mine now would understand and I'd have to open the door for them 
Did you think you were poor growing up?
This made me think.... What do you think?
What did you you think you would have by your current age that you don't?
