You're right Mashie to draw attention to the futility of taking a temperature reading at a doctors office , except when the reading is grossly high, as in a fever.
I'm minded (off topic I know) to draw a comparison with taking a blood pressure reading at the doctors office too.
A patient has been likely driving through traffic, has trouble finding a parking place, exerted themselves getting into the office - and then sat anxiuously awaiting the call. Their blood pressure is raised! Is it any wonder?
I walk to my infrequent visits to the doctors surgery. My blood pressure is taken and it's high ish. I walk back home, rest for a short while and then use my sphygmometer (varied spellings) and the BP is the same as all my other weekly home checks!
There's a wide range of systolic and diastolic pressures between borderline high and borderline low - what your norm is, is more important! And that applies to temperature too.
We playdocs who measure our patients temperatures, by whatever means, are 'playing' since we know nothing about that patients norm. Long may 'playing' continue but we shouldn't get too hung up about accuracy.