Maybe it just likes you?
Then again, maybe you got one of those rare experimental versions of the 5210 series. Nokia was running trials on signal intensity and how much radiation a mobile could safely emit.
The idea was to have the user give feedback after every increase on signal intensity.
Once the user failed to respond to those messages they'd know the emission was too strong...
(Hey, this should go to the "Let's create our own urban myth" section...)