In my experience, nothing but wasted weekends, no-shows, empty promices, waste of time. End of story. Over the past six years I've been begged to lend a hand with invalid carriages for filming on four occasions. Each & every time it was all "Oh we'll be there at X-time on the dot to pick the car up. All it needs to be is clean & tidy, you just see it over to our man with the trailer, he'll give you the money, & it'll be back that night" Each & EVERY time it was always the same; four in the afternoon & "Oh, it's you, we decided not to use the car, nah, we're not paying you never mind what I said yesterday." I've had this from independent film crews, the BBC & Channel 4. Now if ever I hear the opening "We're making a documentary/film/whatever & are looking for...." I just say "Not intrested, I've been messed around too much before by you film crews before". They then always say "Oh, but we're different, we won't mess you around, we really really want to use this car"
Yeah, and so said all the others.