How to prevent visitors from touching your system

Interesting. I have never had to say a thing. No visitor has ever even reached out to touch anything. This could be either my system is intimidating (lots of boxes and knobs) or we have different kind of visitors or both. 

Most of the folks I hangout with, have nice boats,cars,motorcycles ( common interests)  The few times friends have been in my listening room, all (so far) have shown respect for my gear. My wife won’t even touch anything, and I’ve offered to show her how everything works. She isn’t interested.

My friends have their own hobbies. They for the most part understand that entering my listening room doesn't equal an invitation for them to touch everything. They might touch a speaker to feel the finish or pick up an album from my rack but they aren't turning knobs and pushing buttons. It goes both ways. I wouldn't go over their house and touch their stuff either. 

House of stereo.

They get it.

No touch.

When I got my first JBLs, Dorian S12 we had a cat. He liked the grills a bit too much. Being the 60s and in Chicago there were tons of plastic furniture cover makers. Had 2 flat bottom bags made of clear vinyl. Put over the speakers. Worked like a champ. Cat tried a few times but all he did was slide so he gave up.