Ubuntu Security :: Running Wine Under A Different User Account?

I've written an article on my site which lays out steps for installing Wine and running it under its own, separate user account, so that Windows applications cannot access personal files (particularly those in your home directory).[URL}..i'm hoping that there are people on this forum who know Ubuntu inside-out, as I'd like to know how effective the described method is at trapping Windows applications so that they cannot read or write personal files or directories.

The way I understand it, once the process is running under user account wine, it's stuck with the access privileges of user wine. But are there ways in which a rogue application could break out of this prison and gain access to whatever it wishes? I'm guessing that such behaviour would mean someone customising Windows software to recognise Linux, and that such a thing is very unlikely, but I'm still interested to hear what gurus of the Ubuntu internals think of this method.