Proxies worth buying?

I've had this discussion with a friend who bots on multiple accounts. I don't bot myself but since I'm a Java programmer I'm interested in how it works. He bought 10 socks4 proxies and uses a different proxy for every bot client he's using (on the same computer).

Of course checking on IP addresses will be one of the first things Jagex will do once one of his bots will get caught, and if the behavior of his bots is pretty much the same (running nearly 24/7, only fishing or woodcutting), they will ban all of the accounts.

However my guess is that every Java installation on a computer will have some sort of unique ID. Just like Shockwave used to have, where games sometimes banned your Shockwave ID, which you could easily evade by simply reinstalling the Shockwave player.

When I see that you can use JNI within applets, it shouldn't be too hard for Jagex to obtain such ID, or even the complete computer ID via JNI.
http://stackoverflow.com/questions/1713403/calling-a-dll-from-an-applet-via-jni

I'm no expert on this, and probably nobody here knows if Jagex uses this data to detect whether there's multiple accounts playing on one machine. But I think it's safe to say that it should be possible for Jagex to detect multi login unless you are running each bot in a different virtual machine (with VirtualBox or VMware) and a proxy for each of them.

What do you guys think? My guess is that paying for proxies is a waste of cash unless you run your bots in virtual machines.