In other words, the nickname reservation protocol that you're defining
with the NICKNAME mechanism in MSRP shouldn't be limited to MSRP. My
suggestion, for what it's worth, is that you (1) split the nickname
reservation mechanism out into a separate draft, and (2) use either SIP
or the XCON Conference Control Protocol instead of MSRP.
I think these two are actually reasonable suggestions, as long as the
same disclaimer we have in the draft still holds (namely, scope it for a
particular room only, first-come-first-served policy, defining "sticky"
nicknames out-of-scope, etc.).