On the u18 rule of not being allowed play with the club at senior/inter level, one area I've seen it make little sense is in clubs who are at different levels in the 2 codes.
For example a club like Fr o'neills, senior in hurling and junior in football.
An 18 year old in their club can't play with the senior hurlers but he could go out the following week and play on their junior football team, with the same players he wasn't allowed play with the week before.
The rule needs to be revisited, once clubs are accepting that the player gives his first commitment to his own age group and clubs don't try move fixtures for the sake of one player then I say let lads play away if they're happy to do so