Yeah, that. Years ago I roadied for a reasonably popular death metal band (semantics, semantics!) and we played at a popular and now-defunct venue in Brum, with a big Swedish band headlining. We turned up with all our gear, got set up etc etc. No sign of the headliners yet, but no bother, early enough in the day. Eventually they turned up and said "We use your gear". I wasn't happy about this, as a) we hadn't been asked about this by anyone prior to the event, and b) they didn't even say please. I asked the band what they wanted to do, and they agreed to lend their gear (I wouldn't have done this, but they were in awe of the Swedes). When I say their gear, I mean all of it. This band hadn't brought any equipment with them at all, other than plectrums and drumsticks.
We had to hang around until the wee small hours before we could load out and we didn't even get paid for the gig, let alone the hire.
From that day onward I've insisted on knowing the exact crack with everything to do with the stage and gear before committing. I don't mind helping out when there's a crisis but I'm buggered if my band is going to be used as a fee-free rentals service whilst someone else takes the bunce and skips merrily off into the sunset.