Classifieds Sellers advert updating!!

[Shiggsy]

I have been using the PH site to source a Porsche 911 and I have become very frustrated at the number of cars which are still visible on the site which have actually been sold but the seller does not update the advert to state that fact therefore wasting buyers time chasing something that is not available.
I am sure many other users have the same frustration so is there any way PH can improve this by sending reminder emails/texts say weekly to ask if the advert is still valid and prompt the seller to remove or update the advert if it has been sold.