Yeah, some files are still in use after ripping a cd:
tc@box:~$ lsof /apps/ripperx-gtk1/
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
ripperX_p 4296 tc txt REG 7,62 4012 50 /apps/ripperx-gtk1/local/ripperx-gtk1/bin/ripperX_plugin-cdparanoia
cdplay 4297 tc txt REG 7,62 8832 150 /apps/ripperx-gtk1/local/bin/cdplay
ripperX_p 4302 tc txt REG 7,62 3044 45 /apps/ripperx-gtk1/local/ripperx-gtk1/bin/ripperX_plugin-lame
tc@box:~$
I don't think we should use "umount -f" to forcibly unmount and uninstall scms as I don't think it is a good idea for the uninstall function to kill a binary or process that is perhaps actually in use, possibly for an important function. But if you want to be able to find and kill any open and unneeded processes in an scm mount point to allow it to be uninstalled, the below script should work, it did with ripperx-gtk1.
for I in `lsof -t /apps/ripperx-gtk1`; do sudo kill "$I"; done