Anything posted on an open site can be read by anyone. Even the seller...
I've often thought "Sellers could be reading these posts."
I made the same mistake years ago on a now ancient (for computer hardware) Yamaha synthesizer sound card. They were discontinued, and one retailer had 6 of them left. I posted about it on a forum, and would up empty handed. Utlimately, it worked out for the best I found something the could be made more versatile.