Does anyone have a technique on creating unique ids for tables (as primary keys) besides the VFP sample that uses NewId()??

Our problem is our users want to connect to the data (via drive mapping), sync their data, disconnect, modify information, reconnect and re-sync (sending their updates ..and receiving anything new that has changed since they were off-line).

Could off-line views be an option(???).
Does anyone have any pros/cons of off-line views??
or other solutions/suggestions.
TIA