yes it would still be 'stealing' if the performance was not charged for, as it is taking away a revenue stream from the rights owners as it would be a public performance, a film for example that would be paid for should the invited viewers wish to watch by other means..i.e. pay tv or dvd.
As an example to the above though not directly the same, if I download a film, and then watch it (thats the point at which the offence occurs), I would not be justified in arguing that I would not have watched it if I had to pay for it, so therefore I didn't 'steal' it.
A better example....Pub's in the uk broadcasting football as an example, should (and possibly on the whole - do) pay for the right for the public performance rights, to make up for the lost revenue that might occur to the broadcaster from lost subscriptions. Pubs don't charge the viewers for such events.
Will try to supply the info for broadcast rights in due course, and possibly a fee may not be payable, if written permission is given for the performance.
Some people are up in arms about banks going belly up, stockmarket falling, how would you feel if your shares in SONY for example, are losing you money cus people are showing your movies for free.
I know its an example in the extreme, but its very valid.