Drained on Drainage and Home Warranty

It seems that every two months or so I get called by my tenants about some drainage (shower, tub or kitchen sinks) don't drain. It's rooter time again. Why is that tenants simply don't get the idea that they shouldn't put stuff in the drain other than liquid? It's often the hair or undigested food by the garbage disposal. By the way, who came up with the idea of garbage disposal - a rooter professional? This thing gives people the mis-perception that you can simply throw things into it and out came some liquid or something. It doesn't work and it should be banned!

This time I called my home warranty company. Their standard requirement is that they must have the clean out to do a rooter job or the job is not covered. How convenient! If the drain pipes are easy to clean out, I wouldn't need them. I often question the value of home warranty. Yes, I did get something out of it when the water heater in my home broke and they replaced the heater for me, which is already worth the cost by itself. Also, one time my garage opener gear broke and the home warranty company took care of it. However, most of the other times, they didn't cover the drain over x number of feet or drain without a clean-out. It's one restriction after another. Whether they cover it or not, they still charge the standard deductible rate of $50 (in my case). Well, the problem with an insurance policy like home warranty is that you can never win in the long run, because they've got the math all figured out - they will make money anyway.

In any case, is there a way the drain can be designed to be self-cleaning? How about a rooter robot that can search out the stoppage and cut through it? If someone can design a powerful and inexpensive rooter robot, it will sell like hot cake. And I will be the first one to buy it.