Whilst I participate in the secrecy, I really don't think this is a viable long term way of protecting the site. I've been concerned about the axe factories for some time. Just as there are detectorists that think they own our heritage, we also have a very selfish breed of lithic hunter that:
1. Collects as much as they can (The chap who decided to fieldwalk Ladybridge two months before Tarmac did their survey for example)
2. Refuses to report their finds (the chap that brought me 4,000 flint artefacts and disappeared sharpish when I started asking where he got them and who he reported them to).
3. Hunts down sites likely to be rich in artefacts, does not care about scheduled status.
I know of at least three people that fit this description and visit Thornborough often. Thornborough is still not that well known a site, I've seen many fieldwalkers around Avebury, but notice very few finds recorded on PAS.
Is it not time we started making more of a fuss about this sort of thing? Surely, keeping stum is just allowing the problem to continue.
I guess in order to shout about a thing, you need to offer a solution. Here's a few suggestions: More of a straw man than any serious conviction on my part.
1. Make all buried historic artefacts older than 1,000 years property of the crown.
2. Create a new level of protection - historic landscape - a wider comfort zone around scheduled monuments that can take into account the landscape setting of the monument.
2. Make searching for such artefacts within the historic landscape illegal unless a licence has been granted.