Stairs

I have my robot vacuum upstairs and I am afraid to run it without something blocking the stairs. Do they fall down the stairs if or do they see stairs? I would like to run my vacuum more but I’m don’t want to find out he will just keep going.

I have one on the second floor with stairs and a step down bonus room. It has never fell off onto the stairs nor has it fallen into the bonus room. It runs daily.

Mine runs daily and has never fallen down the stairs nor has it fallen into the step down bonus room.