Be grateful you have such a facility as a cast and crew video - here in the UK video in any shape or form is specifically banned as part of the contract. No video recording even for educational or any other use. People still do it, of course - but I've never come across much UK copyright material on the net.

Yes. It has many benefits in the school realm and why it is puzzling and disappointing that R&H stopped selling them. With the license, students and parents put more into the production because they knew they'll be able to see it. It also was a mechanism to teach respect for IP to both students and parents. Now it puts the parents in a bind.

Is it against law in UK or just that all the publishers pact together?

Well - it certainly infringes copyright as it's a specific clause everybody signs up to. It isn't so much that there'd probably be fines involved, it's that if a school or college were proven to have done it, it's highly unlikely Weinberger or Warner Chappel, the two big ones here in the UK would then license another - and places that have performing arts as a big part of their portfolio can't take the risk.

Maybe because the user base here is smaller, these things tend to get noticed more easily.

Video is kind of allowed under the UK version of the Fair Use Policy - because of the educational link, but the reality is that the copyright owner has to agree with your request for fair use - and most, as they've specifically prohibited it, don't agree and withhold permission, kind of making the fair use concept a bit worthless. Ironically, I visit many UK schools and colleges and video is probably the most common evidence I see of performance standards - but it just gets kept very quiet, and officially doesn't happen, if you see what I mean!

In North America the fact that the video is made by or for a school does not, in itself, bring it under the educational provisions of the Fair Use doctrine. It depends as well on just what the school does with it. If it is used for classroom instruction, such as perhaps the teacher in the drama class putting on the production using the video to critique the student's perfomances after the play and showing cuts from the video as teaching examples in front of the class, then it's likely to be Fair Use. But selling, even if just at cost, or even giving away, copies to their parents as souvenirs of the play, or even worse, selling copies to the general student body to raise funds for the next production, would not be considered an educational use at all and would require the normal commercial use licensing.