Your mum is right! Don't cut them off leave them on. What might happen if the flowers get frosted is they will abort then the plant/s will produce more flowers as there aim is to reproduce seeds, to do this they need to produce more flowers and fruit. You don't say is what size your basket is but eight plants seems a lot when you consider each plant will grow to around 12"-15" in diameter. So this situation may cause a greater reduction in potential fruit than cutting off a few flowers,