Do tf2 clients need .nav files?

[foobar]

I have a tf2 server that sometimes runs bots. In order to use them on maps other than koth you have to execute 'nav_generate' to compile the .nav file in the map folder for the bots to be able to understand the map.

My problem is that new players are forced to download this .nav file which may take a while. Is this necessary for the clients to have? Assuming it's just for bot navigation how would I go about preventing this file for being automatically downloaded when connecting?

[loopyman]

Generally .nav files are small and download quick. Yes, they are necessary.