While the ignoring blocks idea might be dead on arrival, I wouldn't mind gaining a better understanding of the effects of the other idea raised:
BC++ will also not allow BU clients to connect to itself.
If BC++ was in theory a one way system, so it still accepted all the blocks produced but didn't relay transactions to Unlimited clients, what impact might this actually have given sufficient adoption? Could this also potentially result in a fork? Or would it just create gaps in node coverage and cause hindrance to Unlimited users to get their transaction relayed if they couldn't see enough "accepting" peers?
Threads about "client X vs client Y" would emerge again...
I think this is the opposite of what we want with Bitcoin.
As I've been making the case quite a bit in recent threads lately, its an open market, so I don't think we should shy away from such conversations. We could certainly handle them better in future, though. Anything that could potentially lead to a stronger and more resilient system should at least be considered and discussed, even if it means questioning the path we're currently on. Alternative clients do have their uses in terms of checks and balances. Increasingly, I believe them to be crucial to a robust system where we don't just blindly accept what's laid out in front of us. Always challenge the status quo.