I looked at the cost of a can of air for the SSSCAT which is over $10. I found a video on how to refill the cans for next to nothing.
Same here. It might work on Lilith once or twice. Sophie likely not at all. It would work on me every time.Those things scare the poop out of ME every time I get close to one (I forget it's there)
IMO: They are 100% reliable when it comes to me. Far less reliable when it comes to the cats.
Best thing I've found is double sided tape. A few times hitting the tape and they generally don't go back.