Dear carpet guy, just because someone has told a client they have protected their carpet, what protector did they use, did they apply enough and did they do it properly, or have they watered it down. If you use a good protector, and there are some good ones out there than there is never a problem. If you spill a boiling hot tea or coffee on the carpet tell the client to boil the kettle and poor the water on the stain. it will come out, no problem. then all you have to do is re-protect at your minimum charge. I have sold it for many years now and have never had a problem. the client sometimes doesn't want to pay the extra but that's their choice. If you use a good product that you have confidence in then some clients will buy it and that can make all the difference to some jobs. I use flooraseal from prochem or alltec protector both are very reliable, give them a go and then maybe you might change you mind I hope.