Yeah, where I used to fly we had Cubs running either 160s or 180s, and then a Pawnee that had been re-engined down to a 160. Wow. That thing SUCKED!!! I flew Pawnees dusting that had 235s or 260s and they were never more than just a little under-powered...imagine trying to fly on a high DA day, full fuel to fly a 3 hr banner and everything sitting behind a dinky 160hp plant! Climb rate? Yeah right!
AvBug nailed it---anytime somebody talks about flying in any form being dangerous, they must not be doing it right. There's always an element of inherent danger in any activity, from walking down a flight of stairs to taking a flight cross country, but if you eliminate all of the "variable" dangers that you can control, ie decision making, fuel, maneuvers IAW POH/FAR/SOPs, etc then you should look at flying as no different than any other activity in your life. Banner towing SHOULD be some of the most boring flying you'll ever do in your entire life---but most people don't do it that way!