The part that requires miner consensus to authorise the withdrawals
Discussion
That's not how bip300 works.
Miner votes are confs, not permissions.
What happens if they do not ack the withdrawal bundle or if they simply spend the coins?
Consider a scenario where there is $30b USD locked up in a drivechain.
Anyone could broadcast a Tx spending the coins to miner wallets, then RBF it to add an additional bounty, and all miners would need to do is allow the Tx to be mined in order to receive their share of the pot.
Nothing happens if they do nothing.
If instead the withdraw gets 26 declines, the withdraw is cancelled and can just start up again. Nothing is lost.
Who could broadcast it . You say could, but thay could implies much.
Why don't miners broadcast a tx from your wakket right now and do all that stuff yoy describe to it ?
Same reasons. withdraws are sidechain side initiated, notnminer initiated.