Hi,

You could make a protection on tables by events, but this is done for normal access of tables (VFP, ODBC,...). There are other tool wich can make editing to data even there are events and triggers active such "DBView" tool.
Any table wich can be accesed on direct view (file on disk or network) of any type (VB/Access/VFP/....) can be tampered with a right tool (Access databases with password can be unloked with a simple hex editing tool like those in VFP example by modifying 8 bytes in Access file)
The most secure data store from modifying and simple access of data is SQL server