Hmm. Maybe you could put the command in the users.txt and groups.txt. This would work exactly like the allow and deny for ULX commands. Benefits? Well all the permissions would be in these two files and they would save between server sessions. Also permissions would be tied to groups or users id, instead of just player objects).
Example for groups.txt (I only use user.txt for immunity, but I'm sure you could figure out how it will look for users.txt):
Out{
//Other groups omitted for example
guest{
allow{
"1" "ulx votekick"
}
deny{
}
toolallow{
//Only needed if something is globally omitted.
}
tooldeny{
"1" "spawn_tool" //VMF Suite spawn tool. Name is of the Lua file. Just like how ulx tooldeny works.
}
}
}