This is a tricky one to find some middle ground for.

In the days of paper we used to send entry forms to all affiliated clubs for a major sanctioned event. Now it's all done electronically...

By the same token, I don't need to be skipping over ads all the time when I'm reading a club thread.

Maybe the middle ground has something to do with engaging with the thread, tailoring the message for them, and not just leaving never to return again after posting the message. That's a lot of work for someone, but maybe that is the polite thing to do.