source?

Whether they reject it or not, it’s less likely they would follow forwarding rules.

Based on what?

If you wanna gamble on this solution, that's definitely your prerogative. I think it's unreasonable to assume that any function of your account will continue to work if it becomes locked, inaccessible, or possibly compromised. A better backup is a custom domain. Which, of course, is not really great with Gmail.

There’s no reason to believe email delivery would stop working just because your account is locked. Such misinformation lol.

Let's flip it around: why exactly wouldn't email delivery stop if your account is suspended or locked?

Because a 3rd party could cause the lock?

Also I have a custom domain, so I don’t consider this a gamble—more of a backup.