Any additional denying/rewriting means more server steps, more server log lines, more wasted resources. If you don't care, send them packing to nowhere, a la:
RewriteRule .* http://127.0.0.1/ [L,R=301]
Thing is, they won't care. Best step? Ignore them and move on.
Make content, not war:)
Heck, be glad they're hitting as infrequently as they are. To me, hammering is more like upwards of 10 pages per second, not one or two an hour. THIS is hammering... [webmasterworld.com...]