That's actually a very very fair question.
Besides coins, another one of my interests is the weather and the number/location of weather recording stations does seem slightly biased to this observer.
Many decades ago (and over a century ago in fact), one of the recording stations which time and again came up with top readings, was Raunds in Northamptonshire. There is still a legit weather station there, and it still registers interesting readings (see link), but you NEVER ever hear that name mentioned for readings or records. Raunds is a perfectly reasonable semi rural South Midlands weather station, typical of many which day in and day out do a great job. But not a single word do you ever hear of them. I mentioned Raunds as it has been famous in the past. But there are others scattered over that area and the Home Counties, such as Rugby, Milton Keynes, High Wycombe, Banbury, Meriden, Buckingham and Oxford - all of which are locations which can reasonably said to represent England as a whole, and are in non biased locations. But again, you never hear mention of them (occasionally Cambridge crops up, such as for the previous record high in 2019)
There are also numerous officially recognised recording stations in the North of England, which again you rarely hear about. Although with that said, we did hear of one on Monday night - Emley Moor, which recorded the highest ever minimum temperature of 25.9. That was surprising given the Northerly location. It's quite high ground as well, and that may have caused a bias. The old ITV tv transmitter at Emley Moor was brought down in March 1969 by a thick coating of rime (layer of ice caused by persistent freezing fog), which caused its weight to increase massively on the side facing East.
But back to your original point, yes, I think there might well be a logical case for excluding airports, especially Heathrow and Gatwick as their readings could well be biased upwards given their urban locations and concrete bases. All weather stations use Stevenson screen thermometers, but what they're sited on, and their proximity to other influences, may well make a difference.
There was bias in the old days as well. Many earlier records were set in Camden Square, London, which was an urban location later considered too biased to be meaningful. Yet they use Heathrow? link to Camden Square info
Photo of Camden Square as it was when used as a weather station:-