Cancelling a join survives a handover
Cancelling a join after the coordinator handed the role to someone else now takes you out of the team, instead of leaving you listed.
If the coordinator had let you in but your Mac had not finished joining, and the coordinator then handed the role to another member, pressing Cancel used to leave you listed on every Mac. Your Mac now signs the cancel, the Mac that let you in passes it on to the new coordinator, and the new coordinator checks the signature before taking you out. Nobody else can cancel for you.