They would continue to broadcast until rebooted, yes.
However, this would also hold true if they were isolated from the network. If the auto-recovery feature is disabled and they lose link to the switch, you have created a honeypot that will cause issues until the AP's link is resolved, not solve them. Normally, it would honeypot for the default 30 minutes, then reboot and stop broadcasting. Signal would be lessened in the area, but people would associate to the surrounding functional APs and still get online.
A ZD hardware failure is far less likely than an AP going offline, so we have yet to use the autonomous network option (actually added in 9.7, not 9.8), for this very reason.