Yes, I am also aware there are/were a couple of variations on the "free postage" option - I recall we had some problems a few months ago when trying to set up "pick up only" listings. In the end we had to also put PICK UP ONLY in the title to 'help' those browers/bidders who do not bother to read the descriptions....

We had to cancel some listings when we got a run of interstate and even overseas people bidding on our pick-up-only listings.

Glitch or not, the seller is responsible for making things VERY VERY CLEAR - my suggestion is add info to the title or have the important info at the start of the description and not way down the bottom.

Other solutions as has been already suggested: pick up only, or calculated postage. Can you also request for potential buyers to contact you for a quote before placing a bid?