MY robot vacuum is great but every time it runs around it closes the vents on my floor registers. If I don't remember to open then again then the air floor for the house is all messed up and I get some whistling sounds from the closed registers. I made this little wedge and top panel to slip into the little channel for the open and close handle to keep it from moving. It is low profile so you shouldn't hit it with your toes and the vacuum should just run over it without picking it up. 

Work with air deflectors as well!

Alternatively, if you want a register to be closed and remain closed then use this on the opposite side of the locking channel.

I know it's quite a niche print but I can't be the only who deals with this annoyance. Enjoy.