Question for moms

So I've been a full time nanny for the same family for 2 years. I love the kids and the family so much, but the kids play their mom like a fiddle! The second she leaves they are instantly happy and the moment she walks in the door they are falling over crying and whining. They speak to me and use manners and when she's here they whine and scream to get their way. So moms, how offended would you be if your nanny told you (nicely) her observations?