Confused re. 'Messages' ...

The ISP that I use transmits 'messages' that aren't too intrusive and I've
previously dealt with by reducing the size of my window and ignoring
them (except for a couple that are really irritating).

The other day I was fooling around and decided to play with the 'cookies'
sent to my 'puter and discovered something interesting: Deleting the 4th
digit from the end of the cookie sent by my ISP resulted in two things:
1) No more 'messages';
and 2) No more 'You will be disconnected in five minutes'
when I've gotten into reading a long file instead of saving it to my HD and
reading it later.

Anyone know why? Or was it just a fluke?

Curious.