I dont have the link to it, but Paul has indicated several times that while they dont really care if people tape their shows they are not going to encourage it or tell people to do it. I have had the oppurtunity to actually ask him about this in person (of course this was in 1997, so maybe he has changed his mind) and he said about the same thing to me about this subject. The
reason? Because of U2's contract Island/Interscope has exclusive license to any U2 material, live or studio which obviously would include concerts. So it really is not up to U2 on this one. The only way it would be is if they negotiated the allowance of it in their contract. First, they are not going to re-negotiate their contract for this issue. Second, they dont care enough about it to even make it an issue in their contract.
I'am not saying its impossible either, I just saying its very unlikely and while I think your efforts are noble they would be better spent towards an objective that may be more feasible and more rewarding IMO. Official soundboard boots of each show is really the wave of the future as I pointed out, alot of artists are already doing it. I know Clear Channel is pushing it with alot of their artists also. So I think there is a much greater chance of that being pulled off versus an official taping policy and who knows, maybe a huge petition for it, like the Slane one, will convince them to do it. It is a major money generator and it eliminates bootlegging. They could even donate the profits for it to charity if they wanted (like the Who did) and avoid the "selling out" flack that also might result.
I think both are unlikely unfortunately, I'am just saying the official bootleg option would have a much greater chance of success.