Are there no decency laws at their local swimming baths? We can only assume this isn't the mother/child hour. Lynne is showing seven eighths of her rear while 'Mantha's bikini top needs some serious re-adjustment. Trevor has every right to look at them if only to tell them to cover themselves up.
How presumptuous of Lynne to think that Trevor was going to be looking at them. To be fair to Trevor, he was only looking at them and not caught with them as Lynne says. If he was caught with them, this implies that they were more involved than just standing in the shallow end. Lynne must have also seen Tina on the warpath. What she should have said was "Look out. Here comes Tina to have a good go at Trevor who is clearly staring at us." Unless of course Lynne has some sort of psychic powers. If she has, she should put them to better use than to predict marital strife.