What is it with these people? Would it be OK for me to go outside and start playing with their cars?

Absolutely. You should insist.

About 15 years ago, a very large biker sat down at the B3 when I snuck off to fetch a pint. He wasn't bad at all, but I still couldn't let it slide. I gave him a nudge and told him to either get lost or give me the keys to his Harley. He handed them over without hesitation, so I went for a ride while he played a few tunes. He didn't beat on the Hammond, I didn't beat on the Harley, and we both had a little fun making noise with each other's toys.

If you're driving a Toyota, that wouldn't float.

About 15 years ago, a very large biker sat down at the B3 when I snuck off to fetch a pint. He wasn't bad at all, but I still couldn't let it slide. I gave him a nudge and told him to either get lost or give me the keys to his Harley. He handed them over without hesitation, so I went for a ride while he played a few tunes. He didn't beat on the Hammond, I didn't beat on the Harley, and we both had a little fun making noise with each other's toys.

About 15 years ago, a very large biker sat down at the B3 when I snuck off to fetch a pint. He wasn't bad at all, but I still couldn't let it slide. I gave him a nudge and told him to either get lost or give me the keys to his Harley. He handed them over without hesitation, so I went for a ride while he played a few tunes. He didn't beat on the Hammond, I didn't beat on the Harley, and we both had a little fun making noise with each other's toys.

Really infuriating. Haven't had it happen in a long time, but this always worked for me: if I saw someone doing it, I'd walk up immediately and turn the keyboard off and firmly say "that's enough". I wouldn't be polite, but I wouldn't be rude either. Usually they 'sort of know' they're doing wrong, so no explanation is needed.

How do the rest of you deal with crap like this?

Even a hard stare from my direction only stops him playing it - he continues to sit there like an idiot.

...pointing out that she was fooling around with a piece of equipment that cost the best part of two thousand quid

It's got so bad recently that I'm at least thinking of making a couple of laminated "keep off" signs to stick on the boards during breaks.

The part of that story that I can't quite comprehend is where you nudge the (very large) biker, and tell him to get lost or hand over keys.

One of my favorite ways to deal with this is to set the keyboard on "lock mode". The CP300 is the only keyboard I've had that can do this but when it is in lock mode no settings can be changed, patches can be changed, etc. So if I think some nut is going to sit down and play I just set it on a really nasty patch- like a sitar or glockenspeil- and lock it down. After 10 seconds of frustration they leave.

One of my favorite ways to deal with this is to set the keyboard on "lock mode". The CP300 is the only keyboard I've had that can do this but when it is in lock mode no settings can be changed, patches can be changed, etc. So if I think some nut is going to sit down and play I just set it on a really nasty patch- like a sitar or glockenspeil- and lock it down. After 10 seconds of frustration they leave.

You know that after-market car alarm system sound? It's like a collection of all the different siren noises from the last 50 years? Have a sample of that in there, and leave the kbd and amp turned up to 11.

When we do the on-the-floor, no-stage type of functions, we always put a velvet rope in the contract rider. Every hall has access to one and they discourage people from crossing if they're set-up around the entire front of the performance area.