locking, permissions, data

[Peter Alcibiades]

Here is a very weird situation.  The program consists of a launcher, call it 
launcher, and the program proper, call it program.rev, and they are both in 
the same folder.

I get a call that launcher is not starting up the program.  On inspection of 
the folder, one sees the following:

launcher [executable, 2.5mb]
program.rev [unknown, 20k]
program.rev~ [unknown, 300k]

So, I delete program.rev, remove the tilde from the other name, and everything 
works fine.

The only way I can think of to account for this is that someone opened the 
program.rev file in a text editor, and then saved it.  All Linux text editors 
I know seem to make a backup copy with a tilde to distinguish them, on 
saving.  

Yet, the users at the time are definitely incapable of opening a file with a 
text editor and then saving it.  This is the second time its happened.  

What to do?  One could make program.rev read only, but then it would mean that 
all the data would have to be stored in external files, and then read in for 
any processing, which is getting very complicated.    Is there some way using 
finely grained permissions to stop this happening, but to allow data to be 
added to the data fields and custom properties?  Should I perhaps make the 
default application for the .rev extension something totally harmless like 
maybe mplayer?  

Any ideas on how it could happen, and what to do, gratefully received!

Peter