Most common reason....things like Top of Pipe/Btm of Pipe vs Top of Insul/Bottom of Insul vs Centerline tend to get changed when annotating. If it's network, you gotta lock people out or they keep stepping on each other.
Easiest way to to have it local. A simple script to keep the local sync'd is all that's needed, you just exclude syncing the CADINFO.MAP.
Alternatively, you could place multiple "user" folders on the network, each with their own MAP.INI file and use relative pathing to have all of them point to the same database. CADINFO.MAP resides in the same folder as MAP.INI so each user would be mapped to a seperate MAP.INI (hence seperate CADINFO.MAP) but the relative pathing would point them all to the same database.
I don't do this per user but I do per trade so that pipe fitters see Ft-In dims for lengths and no dia symbol for round but sheetmetal guys see fractional inch lengths and get a dia symbol for round duct.