Sunk Without Trace

You may recall that we visited the National Waterways Museum at Ellesmere Port a while ago. I was very impressed by the museum and facility, but surprised at how many wrecks were lying around on the bottom.
Now I know that with wooden boats, this is the best place for them if you don't have the money to repair them and return them to their former glory. However, I was slightly concerned that visiting boats were navigating around the various basins of the museum and the wrecks weren't marked.
To a mariner like myself, it would seem sensible and quite inexpensive to secure marker buoys to each end of the wrecks, so that boats who are quite low in the water themselves would see them.
A recent comment on the blog of NB Caxton suddenly brought my attention to this here:

http://narrowboatcaxton.blogspot.com/2011/04/ellesmere-port.html