Okay, as a mother of a small child, do you really think that my three year old is going to understand when I tell him "here comes the safety lady..." ? He doesn't care, and it doesn't get his sticky grip off the can I'm trying to get from him. Maybe the remark was a tad bit insulting to you, but I think you're reading too much into it....you would have been equally as insulted if the mother had allowed her child to retain his beverage until landing because it's so unsafe for YOU to have to get up and get it two seconds before wheels down because she didn't listen the first ten times you came through.
She was getting her child to comply with your request and, I'm sorry, but to a three-year- old , at that instant in time, you are the trash lady, even though it doesnt define you, it does to him in the three seconds that he's going to see you for. And never remember probably.
I would understand if this was someone to their husband or friend, but a child?
Don't let what an infant might possibly think about you ruin your day. SO not worth it. I guarantee you neither one of them will think of you again once their off that plane unless you were either super nice or a bword.