Does pay per click advertising help or set you up for abuse by competitors?

[upwardly_mobile_home]

I own a service business. I serve a radius that goes about 25 miles to my north and west, about 35 miles to my east and south (the direction of wealth and more densely populated areas).
Now I get 2-3 clicks per week from the poorer, rural areas each week. About 50% of the clicks lead to calls and nearly 100% of the calls turn to work.
I can't say that about the more competitive market. I get 7-10 clicks per day. I am lucky if 10% of the clicks generate a call.
In the non competitive market, I might pay $2.50 per click. In the more competitive market, more like $5-6 per click.
I suspect competitors are clicking. I cut the bid by 25% in the towns where competitors are, the number of clicks drop in half and I still get the same number of calls. This leads me to believe many clicks are abusive.
I will admit it, I click on competitors ads once every 6-8 weeks. I am curious, but not abusive. If a new advertiser puts an ad up, I probably will click it to check them out. If I click 1-2 ads in a month, that's a lot for me. I strongly suspect that others are clicking to be spiteful. Do you agree?