Your right and on reflection I may just be making a set of worry beads.
The temp reading returned will only ever be representative due to several factors and as you say the bees are very effective at controling it, if they are in cluster or not and that depends more on ambient temp.
The tag cannot be in the centre of the cluster anyway.
Intervention in the hive in winter, apart from supplimentary feeding that should have been started earlier, is often ineffective and impractical as well.
Movement detection is another desirable but not essential featue and I can think of only two issues in the past four years where it would have been useful but again not essential.
My bees have survived so far despite mans interference that may yet prove fatal for them and provided I manage them I hope will continue to do sa.
Lets let it rest for the time being . . . . . .
Thanks
AndyC