I wouldn't chain it to anything, that would seem like you're escalating the battle. Painting it may also violate the chemicals part of the bylaws, depending on what you use. Building it into the banks seems like a good idea, you could also use heavier peices of wood that are more cumbersome to move. If there's space and the lead-in fits, you might also try building few kickers instead of bridges.
P.S. In before illegal-trail-mod-nanny.