DFC,
If there was a hard frost how long do you think it would take for the frost to melt from surface areas and aircraft in the shade if the OAT is only reaching +3? Remember that with an air temperature of +3, the ground temperature can be far less and with some windchill in the shade forget about the ice melting quickly.
The point I think of the thread is not the specific items that we all know and work with daily, but the dissimilarities between one ATC unit and all the others.
I personally don't care about these warnings, they don't bother me, but just curious enough why only BRS have adopted it, which is what I think the original thread starter meant when he/she started it in the first place.