GenerationGap it's not really the point is it?!
If it makes my life easier and my childs treatment better for me to stick a thermometer in her ear, so that the doctor can go "oh, that is high, let me check on her" or "that's about normal for a cold, just chuck some calpol down her" then I will do it. Ditto my own treatment.
My doctors for the last few years have wanted to know. Who am I to deny them this easily obtainable information?
It's not like I am being asked to do anything illegal, immoral or fattening. It's a simple bloody test, not a complicated medical procedure.
And even if the result is not totally accurate, it is certainly not totally unreliable. Furthermore, I think everyone here would agree that if a thermometer was telling them something counter-intuitive, they would disregard the thermometer.
If it helps, it helps. If it doesn't help, it certainly won't hurt.
Stop being so down on something that you've made it clear you have no experience of.