I've run my library in this configuration for at least a year and never had a corruption issue, but I recently changed to a different solution due to problems with MC accessing the database on a remote Windows fileshare. (Have you noticed the UI freeze in MC when it is "Saving Database" on the machine where the library doesn't live?)
The way I do it now is much better, and much safer too, because I get automatic backups of the library once per day!
Basically, I wrote a few scripts that copy the database to and from a centralized location on an automatic basis, and then scheduled the scripts to run regularly on the systems. This doesn't keep them in PERFECT sync (because if I tag some files or import them on one of the machines it doesn't show up on the other until the next run of the "import" script). However, it is safe and allows you to do what you want.
Basically the way I have it set up is:
2 machines.
1 is my Primary Computer. This is where I typically do all my importing and tagging of files.
2 is my HTPC. Because it is inconvenient, I typically don't do any major tagging on this machine. When I do tag some files, I run a separate script when I am done to "publish" these changes back to the master copy.
I have three library locations, though 1 of them is never directly used by the running MC copies. Each machine has it's own "local" library located at c:\library_data\ and there is a separate library at m:\library_data\ (drive M is my media "drive" which is actually a SAMBA share running on my Linux server, but could just as easily be a Windows file share mapped as a network drive). The M drive library is never directly accessed by either copy of MC, but is kind of the "shared" library.
Then I have a few scripts that copy stuff around:
1. Copy the library from the Primary machine's C:\library_data\ location over to the M:\library_data\ location on a regular basis. It also makes a zip archive of the old library once per day (it skips the thumbnail folder which is huge) which is nice in case something stupid happens.
2. Import the library from the M drive to the C:\library_data\ on the HTPC computer. This runs daily, which is enough for me, though you could easily modify the script to do the import (which since it doesn't touch the thumbnail folder doesn't take long) and then launch MC and just point your MC shortcuts to it instead of the actual MC program on the HTPC.
3. Archive old MC library backups. I have a script that runs once a month and clears up all my old ZIP backups. It also creates a backup in a different location and keeps those for the long term (so if I ever have a big screwup I can at least go back to the last month's library).
4. "Publish HTPC Library Script" This one is still a work in progress, but the idea is that it will be an icon in the start menu (or wherever) that I can hit and have it Close MC on the HTPC, then copy the HTPC's current local library over to the M shared library and to the Primary PC's library. This is so that you can manually "save" any changes you might make on the HTPC side (if you do decide to do a little tagging on that machine for some reason). The reason it is still a work in progress is that I'm deciding what to do about copying it back to the Primary machine ... I think I have two choices. 1) Automate SSH-ing into the Primary Machine and running the mjextman.exe /CLOSE command to close any running copy of MC before the script copies the HTPC's library directly to the Primary machine's store. -or- 2) Have the "Publish" script create a "flag" file that the Copy script (number 1 above) checks for when doing it's copy and if it exists it does the copy in the opposite direction.
The benefit to method 1 is that it takes effect immediately. The downside is that it would be a pain to script and I would have to install and maintain an SSH server on the Primary machine (plus it would suddenly close MC if someone were using it on the other computer). The benefit to method 2 is that it is MUCH easier to implement, and seems a little safer (because it never actually touches the Primary machine's database).
I'm still deciding... Either way, if you'd like a copy of my scripts, just let me know. They're tiny so I'd be happy to email them to you (though I'd need a few days to finish the last one). All in all, this is a much better, and safer, solution!