Stop me if you have heard this before, your finishing up some art piece. Be it doing camera shots in the park at a waterfall, doing a contact juggling bit for some spectators, or playing your guitar. As this is going on someone walks up and says, "hey I know how to do that to". A few years ago when guitar hero was all the rage, I heard a few stories about teenagers who thought they knew how to play guitars because they played expert on a video game (Guitar Hero Destroying Music). I even heard a few stories (rumors) about actual guitars getting damaged.
Tonight I did some art gallery work at the Art Alliance in Philadelphia. One of the bit's that I did was a hundred foot rope escape, in order to make it more aesthetically pleasing I went ahead and did it as an open challenge for anyone to work on while wearing a blindfold (because everyone is more impressive when you wear a blindfold ;) ). While I was i this state someone went ahead and actually cut my rope and took off about eight feet or so of rope. Now I can still use the rope that I have, though I will have to replace it. But I am torqued.
I saw the man who cut the rope performing demonstrations of various ways to tie someone in at the hands. I know enough to know that this person was at least proficient. That right there is the thing that burns me so completely, that he as a person who is proficient with rope (as well as the cost of rope and equipment) would without any consideration purposely break, damage, or put someones equipment into a position of risk. If he had asked or offered a trade I would have more than be glad. The rope isn't going to set me back to replace so I am not worried.
The thing that worries me is how common of a practice this is, not asking or touching just doing. I have walked away from my equipment in a gym to use the lavoratory to come back and have about 20 kids going through at least 500$ worth of equipment that I really can't replace with adults just watching. "Oh we just assumed this was campus equipment". I have been to juggle festivals where 5-10 clubs went wondering off because someone thought that the clubs from a friend and I were "communal". A club is at least 30. Three Hundred Dollars worth of juggling equipment that literally could have walked out of the facility. I have seen people literally walk out of friends houses with equipment. And there isn't any sort of negative intentions, they usually just don't have the presence of mind to think about it.
I write this because I really would like spectators and not professional amateurs (be they jugglers, magicians, musicians, etc) to think really long and hard before they start randomly borrowing equipment because you might be the person who breaks the piece of equipment that you can't afford to replace or damage. I have equipment that is "stage" only that is to say I only use it for professional shows or to practice for professional shows.
I also write this because these are also the people who make our lives purposely difficult as performers and people out to make a living. Most people who make a living at an art know enough to not try and screw someone at their art, the danger is when someone knows enough to think that they know enough. These are the people who jam locks, break apart gaffs to show that they are gaffs, yell how something is done to the audience, etc, You can't do anything about these people outside of what you do with hecklers (which depends on the person). You need to learn how to recognize these people and NEVER bring them up on stage, unless you know how to screw with them (one of my personal favorites is to have a "screw" card at the bottom off the deck)