mike, I did just that on a wooden power pole and promptly got a call from our local coop and had the vp who is a friend of my dads not intervened on my behalf they were talking about charging me with some bs trespassing charges for putting a nail into the pole.
every year for the past 4 years I get 100 yard signs made up and stick them out. heck I probably only put out about 75 of the ones I had last year, but already put out 25 of the news ones that came last week. Every year I go with something different and every year I make money of the investment. I get the signs made up one color, one side 18x24 with stands for $3 ea to my door if I order 100. what the heck, its $300 and it always gets me new customers.
I had 5000 brochures made up for $400 or so and stick one in every piece of mail I send out, even with bills. Heck I bet I have customers who have had 4 or 5 of these things int he past couple years. When I first got them I brushed my teeth, washed the truck and spent 3 days driving around the ritzy lakes banging on doors. Within 1 hour I booked a flyer job on a huge log house- over $4k on that one job. I did that last spring and I still get calls from the initial handouts. with the 5000 brochures I also ordered 3000 clear plastic bags to hold them, with a hole to go over a door knob. They do work well but I did have someone call me and ask to never do that again on their house because it did signal to others that they weren't home. I didn't mention to them that the fact that their driveway wasn't plowed all winter may also be a "sign" but they did hire me to remove bats out of their lake home so they couldn't have been too jazzed.