How *are* allotments protected/restricted? I've never seen an
arrangement with huts and semi-permanent participation (in the US).
There are a few "community gardens" locally. One experiment in an
'inner city' area was completely vandalized about halfway through the
growing season. My own plot (20'x40') was on a gov't site (NASA) and
out of reach of most yobbos. Large tools (tillers) were kept in a shed
with a lock all members of the 'garden club' had the combination to.
Hose(pipe)s, sprinklers, and small tools were left undisturbed. The
occasional pumpkin or tomato *would* disappear overnight, of course.

So what are the usual arrangements to prevent theft and vandalism?