If the table is in a database, then yes. If it is a free table then, I dont know of a way.

If the table is in a database, you can specify an update trigger. if that trigger returns .t. then the table can be updated, otherwise it will not be updated. If you wanted the user to be prompted with a dialog box to enter a password or something, you would probably have to put that code inside a stored procedure.

I have a simpler version here. I have a field called mytable.locked
update trigger is set to !(mytable.locked) where locked is a logicial.

so if locked=.t. then the table can not be updated.