Changing my DPI (sensitivity) requires me to press either a button above or a button below my mousewheel, a button which is touched by a spare middlefinger. So, it's really, really easy to pull off.
This talking about how aliases might be a disadvantage to people who do not have/use aliases is basically a cry to remove any kind of customisation from Tremulous, since any kind of of customisation is a 'disadvantage' to the person who does not know about it, or does not wish to use it.