This seems pretty clever. Am I understanding correctly that the fees for the high feerate will be deducted from the balance of the channel opener in the current way? Since we would always expect the mobile wallet to be the channel opener, that means (1) it costs the peer nothing to offer the mobile wallet a high feerate option and (2) the mobile wallet has an incentive to not use the high-feerate option unless it’s actually necessary for safety or recovering liquidity from a stale channel.