I am on the fence about this one. Session files, for me, are almost never useful, as the person doing the mix is generally using plug-ins that I don't have, etc. Also, they may be less likely to consolidate the files, if they know I'm using the same DAW. I like to have a clean slate when I start a mix, of course.
On the other hand, I have, for a while, been thinking about doing a mixoff section with Reaper files, where everyone would commit to using only the stock plug-ins, and to posting their mix session files, for others to see. I think this could be a great way to see how others approach the mix. Using only stock plugs with a DAW that can be demoed for free might be worth pursuing. What do you think?