Also since I am replying again, I just want to mention that windows hasn't defaulted to diaplaying 3 char extensions in a long long time. In fact I would argue that java 6 probably doesn't even support these versions.
Just to be clear, the issue about having the first characters be "unique" were not at all about Windows/DOS 3 char extension display.
It was Brian and me going through the state changes on a machine at Devoxx and viewing it from a file browser (i.e. Explorer and Finder) and noticing that the UI's by default were showing ".dep.." and ".dep..." when we were using .deploy and .deployed as the markers.
That's why it was suggested - not because of ancient OS reasons.