Maybe I'm being irrational, but I really find this infuriating:
It's bad enough that every live music experience must now be branded with something (I take great pleasure in going to Carling sponsored venues and purchasing any lager other than Carling). Now the fact that I don't use the O2 network might disadvantage me in terms of getting tickets for concerts I have just as much right as anyone else to see. I'm not someone who thinks that all corporate sponsorship is evil - and by all means offer special discounts to O2 customers as a marketing ploy. But this priority booking scheme just strikes me as unfair. I hope they will only put a limited number of tickets into the O2 pre-sales.
On the other hand, perhaps there's no difference in principle between this and the BFI offering priority booking for the London Film Festival to its paying members, something I don't seem to have strong feelings about.