Re: Maybe this could work with the right regulations
I was thinking this too.
But I don't think that you can realistically stop those charges getting passed on to the customer, and I don't think you actually need to either.
Say it turns out that O2 actually has the best coverage overall, and 3 the worst, with Voda and EE somewhere in the middle.
O2 will be getting more in revenue from this forced sharing, and will of course reap the profits and not bother to build new infrastructure because, hey, they're a mobile phone company and they're all a$$holes.
3 will end up paying a lot more, to O2 and Voda / EE than they get from the reverse, and will be taking a hit. They will either (a) pass on the costs to their customers or (b) build new infrastructure in the places where they see the problem. If (a) (which seems more likely - all mobile phone companies are a$$holes remember) then their customers will leave them for O2, or Voda / EE. They will eventually go bust, or find a level, or realise they need to build more infrastructure to get a slice of that sweet forced roaming agreement deal that O2 have been basking in.
Voda and EE may do nothing, being revenue neutral here, or they may see the opportunity. But when 3 starts investing and they start being the ones paying more out than they get, they may start seeing infrastructure as a benefit.