I've been pretty lucky that way. It took 6 weeks of having over a hundred tanks in the driveway before someone complained to the township. I started out with about 140 that a friend gave me after he lost his house, and was cleaning them up and selling them. I was down to 40 when I got the letter from the township, so I was able to fit them in my garage without a problem. I was grateful that it took that long, because I had no desire whatsoever to haul that many tanks into my garage or basement!
Another funny story is I have one neighbor that we've always been cordial with, but we never really hung out. I had mentioned to him that I had a bunch of aquariums, but never really pushed my hobby. One day (after he'd been in his house for about 3 years) he mentioned he was thinking about starting up a 55 gallon, I invited him to come over if he wanted some ideas. The look on his face was priceless when he saw my fishroom!