I'd advise mods (especially mprep) to delete all my posts containing a "thank you"
Some of my posts have it too, but (like yours) it's part of a bigger post. I post weekly thank you posts
in this topic, but it's more than just "thanks" and that thread often gets derailed about time travel and flux capacitors anyway.
My opinion: In general, just saying "thanks" is insubstantial. I've reported posts like that many times, but probably not on the Collectibles board. I usually don't report them either when it's a Newbie posting what looks like a sincere thank you on the Technical boards. I can imagine it seems unfriendly if a Newbie gets his post deleted when he was just happy because he found the solution to his problem.
Just a thought: a count down timer to self-delete a post would be a nice feature. Post "Thank you so much for doing this!", click "auto-delete in 24 hours", and in the corner of the posts a count down appears. For Mods it's obvious it isn't spam and will clean itself, and the user gets to say thanks without sending an unsolicited PM.