Cancelling a join leaves nothing behind
Cancel a team request after the team already let you in, and you are taken out again and the invite link works once more.
Sometimes a team lets a Mac in but the answer never arrives. Cancelling the request then left a member nobody could use, and the invite link was spent.
Now cancelling tells the team. It takes that member out, everyone else hears it, and the same link can be used again. If the team's Mac is away, the cancel waits and arrives later.