I was wondering if there's a way currently to check if a user need to download resources for the game or not. This way when a user logs in, you can check if he has the resource files. If s/he does not, you relocate the user to the resource downloading area. This would save a lot of server stress. If there's no way to do it now, could it be implemented sometime in the near future?
Your best bet is to use the preload_rsc variable, this'll let the users download the resources from a place besides the host machine to keep network lag down for other users.
In response to Nadrew
Ahh. preload_src="url to resource file". Most useful, thanks.
In response to Nadrew
It would still be nice to know if they have to download the resources. Not only that, but also when they have finished.

When I used to mess around with fancy intro scenes and effects, people that joined did not know what I was talking about when I asked them how it was; because they did not see any of it.

Either way, it would be nice to know whenever someone is downloading resources.
In response to Loduwijk
So you could build a "loading screen" prehaps?
In response to Flame Sage
Yes. You could link them in the browser to something more visually pleasing than a black map, or you could link them to a web page with instructions or game news or whatever is useful.

Either functions that we can overwrite which are called when downloading starts and stops, or even just a simple boolean variable.