After reading other,s opinions I think the pins should be replaced, or at least the essential ones. I don,t think pins, especially replacement pins, are anywhere near as offensive as a bolt. The point brought up about not being enough beginners, routes in the North Conway area is valid, at least well protected beginners, routes. It seems like a lot of pins are mentioned in route descriptions in the guidebooks to the region, it would be easier to replace the pins than amend the guidebooks.
What if the offending thief had replaced all the relic pins with new ones, would there still be a problem? Are there any unwritten rules to replacing old pins, or what to do with them? As a beginner I used to clip these things thinking they were bomber, until I hung on one in Seneca and watched it wiggle out while I raced to plug a cam in next to it. Luckily it held, but taught me a valuable lesson. I don,t hold much faith in fixed pins, unless it,s clearly bomber, but try to back them up whenever possible. I hope no one messes with the ones on Still in Saigon, they aren,t an eyesore and I think they well placed. Just my humble opinion but I do agree that it's nice to climb a route that has no fixed gear on it, hey that would make for a good thread.