I was at a shop a short time ago where the owner told me that he had made a big mistake degrading his current software point of sale system in front of his staff. What he had done was tell them often that he was upset that the tills never balanced. What happened was as the staff started to realise that the tips did not balance, they gave up caring that they should balance. One staff member listening while he was going through it with me, burst out laughing when he showed me a cash register listing that showed one day they balanced. "How did we do that," she said? It was obviously the staff had stopped caring. Part of the pressure is on top of that the owners knew his software has not been fixed for the Caloundra bug where employees can take money out of the tip without leaving a trace. One point we could reassure him was that our system it could not happen.
Still ask yourself this how will your suppliers, clients and staff think if they even think that there is a problem with your computer system? They know you do not have stock control, what if they know you do not have tills that balance, what if they know you do not check your supplier's invoices, etc., etc.
Security is very much a feeling. If you give a bad feeling, it will become a reality.
If it is no good fix it, ASAP but do it quietly.