I think I'd worry about it. Ask the company about the safety of the spray, specifically in regards to your tanks, they'll probably say it isn't pet safe...then ask about how it's done. If it's a directed, liquid spray that won't be in the air much you might be able to just cover the tanks very well, and maybe add a bubbler running from outside to keep positive pressure inside the tank to keep any gas out. If it's more in line with the whole bug bomb/put a tent around the house thing I don't think I'd feel comfortable leaving my tanks set up.
Edit: Well, I guess even with an aerosol you might be able to get away with sealing the tanks to virtually air tight, then use a bubbler from outside or a compressed oxygen cylinder to keep the pressure very positive. Might work. Oh, and I think it would depend upon where they're spraying. If it's a liquid to the outside of the house I'd be much less worried than something in the same room.