CSV export must de secured

Any data that can be read can be exported.
In practice, before to leave the company, the salesman can export all the customer addresses, all the sales and all products with prices.
As he need these data to work with, he can export it too.
If I'm right, the export of data happen at the client side.
A solution could be to have 2 different GTK client, one with the download option, one without
At the server side, we could define which user is allowed to connect with which client type.
So, the admin can export, the salesman cannot.