They can make your heart rate go crazily high, even if you're just in the same room as an open bottle. I refuse to see clients on non prescription drugs, and even make a point of specifying poppers on my profile. Yes some inhalants are sold in Ann summers, but you'd probably find that most clients get them on the black market as the shop bought ones aren't very strong. The ones they're likely to have bought will probably not be regulated, so if you did have an adverse reaction then it'd make treating you complicated, plus you don't want to be in a situation where you'd require medical help on an escort booking anyway!