What to do for visitors?

I use presence detection for arm/disarm, but what to do for visitors? I'm trying to figure out if it makes sense to still install a keypad, something like 


Perhaps some other method, my Mother in law comes over some times and I don't want to go through setting up presence app for her etc. What is everyone else doing for those kinds of situations?

Also thought about disarm on a good unlock of the front door.