False voids are a simple way to take advantage of the system because, unless verified by a manager, it’s easily unrecognized or overlooked. Typically easiest for a cash transaction; a server receives cash from the patron and, in turn, voids an item on the tab when processing the payment- citing the reason as “unhappy with food”, or something similar. The manager approves the void, changing the total, the server gives the patron their change according to the original total & pockets the difference.
Another version of this is the voiding of an entire transaction that was paid in cash. The server voids the transaction as if it never happened, takes the cash and pockets it. Situations like this can often involve a server and manager because most bars & restaurants require manager approval for voided items or transactions. If you notice a pattern or rise in the number of voids, be sure to look into this further.