If you have neighorhood that is prone to breaking and entering then maybe these sign wouldn't be good but then realtors has flyers with the same thing on it. Also, new constructions are all vacant as well, again it depends on the neighorhood.
These signs are become a big hit here in Eugene and some of the offices (Barnhart, Ranstad Group and Emerald Valley Real Estate)are making all there realtors use these signs. Keller Williams and GMAC has introduce these signs at there staff meeting last week.
http://EugeneGraphicsShop.com