The straight dope: I don't know.

Personally, I don't use Netscape anymore (I still have it on my boxes, but I can't remember the last time I used it).

The way the system is supposed to work is that a request gets sent from your computer to the host. The host sends back a series of commands to your computer, including the caching command, and then your browser interprets the commands and posts the page for your viewing pleasure.

According to some industry rags I have glanced at (I get about 5 or 6 a day and read one every 2-3 months), there is a "new technology" on some of these firewalls or interfaces that strips some of the refresh/open new page commands. This is to help cut down on the extra pop-ups from sites that send a ton of pop-ups when you don't buy something from them (like some of the porn sites).

I don't know if this technology actually exists, nor what type of algorithm it would use. I guess I could look up some articles and such, but I am a little lazy this Saturday morning, sorry. (My last weekend off until end of May.)