I wish it was possible to send an automated message to any people “watching” your trade that you are about to cancel it. I don’t really understand the purpose of “watching trades” if it’s impossible to know if the trade would be taken down. I propose a button that sends and automated message to anyone watching the trade that you plan to cancel it.

For instance:
“A trade you are watching has been marked for cancellation in one hour, if you’d like to review the trade click here”

With a link attached to the trade.

It would be an optional button so it’s also possible to just cancel a trade if you decide you don’t want the items, but if you want a last chance to sell and know you have people looking, I think it would be nice