In practice roughly 0% of senders will react, except for maybe add you to a blacklist of bouncing addresses. If it is in my spam folder at least I can find it i

In practice roughly 0% of senders will react, except for maybe add you to a blacklist of bouncing addresses. If it is in my spam folder at least I can find it if I know I should have it. I've wondered if it would be useful to reject + store in spam. This way I have a copy and the sender can know that I likely won't see it.