Interesting responses all around.
I really have no problems with this whatsoever.
I always hope that it works out for the best.
Sometimes it does, sometimes it doesn't.

Here's another question.

Let's say you have mixed the track ITB and saved it.
How do you feel about all your personal drum samples, plugin settings, ect. being handed to someone else?
Do you feel better giving them a clean slate version of the project?
Should you get a partial mixing credit for handing over what could be considered pre mixed material?
If someone else basically uses your mix with arrangement\small changes are you going to be pissed?

This topic has been discussed at great length already... but exactly how you would find those threads....er... escapes me at present...

Speaking from the perspective of a mixer...I'd RATHER start a clean slate then starting with someone else's treatment and effects.

Part of that is because of my approach to mixing, starting with a DAW and then hitting an analog console with outboard gear. Removing all the plugs and grouping gives me flexibility. On the backside of it, nobody else can recreate my mix because it wasn't done entirely ITB.