All my newly published products have Etsy Ads automatically turned on after publishing, even when I don't have the box selected to turn them on.
Are you creating a brand new listing or copying a previous listing?
I think it’s only new listings.
Same thing is happening to me. I specifically checked to make sure ads was not turned on before I published and $17.00 later I realized one of my new listings was being advertised. I've even made changes and republished this listing - each time double checking to make sure ads was not turned on. It has happened on several other listings also. Every few days 2 or 3 of my listings are randomly being advertised via Etsy Ads without my knowledge or consent.
Yes, at first I thought I didn’t pay good attention, but now I’m paying close attention and it’s not user error.