>How can we protect (modifications/visualizations)
>from pgms

Aluysio:

Novell can protect from access by all but the target group.

To cripple a file NOT in USE, simply use low-level file access
to replace some bits in the file header with a string. FoxPro
will report the "not a FoxPro file" error, and I believe XTree
and others will become useless. It is easy to test. Use this
in your shut-down. Do the reverse when opening, as part of your
error-handler. Your manual has full header information.

Best,
Randy