Yes, generally it is illegal to tape a production (assuming it's not a show that's in the public domain), for any purpose, including "archival purposes". If there was such a permission it would likely be spelled out in the performance contract the you received from the rights holder.

Despite this, what you describe is not uncommon, people either don't know the terms of the contract or choose to ignore them figuring they won't be caught.

Dan

What Dan wrote is pretty much on the mark. Many groups think that they are ok, as long as they're not hawking video tapes in the lobby. Others just 'pretend' like it didn't happen, or assume that it's ok because "that's what we've always done." If you want to be completely legal with your 'archival copy,' it has to be either a) spelled out in your contract, or b) you have to request and receive permission from the right holders. For example, the following was plucked from the FAQ of the Dramatists play service website (www.dramatists.com):

[start quote]
Our theatre would like to make a videotape for our archives/grant proposal. Is this all right?

The agents we deal with are increasingly open to this kind of request, but as usual you must get their permission first. Again, contact the author's agent by writing to them at the address listed on the copyright page of the acting edition.
[end quote]

There is also a document on this subject on the American Association of Community Theater (http://www.aact.org/documents/Videotaping.pdf).

-Tom

"Educational use" needs to be clarified -- the "fair use" clause applies to education (and a few other cases), but with limits.

What tristanrobin said about educational use is true, as long as the performance stays in the classroom. If that same class presented the performance to an audience (meaning presented to people outside the class), it's a public display of a copyrighted work, and is not subject to the fair use clause.

-Tom