Hey babe! Glad to hear from you! Your name always makes me
You understanding that I am all about no frigging lies at all, let me give you just a little twist of opinion. As always, take what you need and blow a hearty Bronx cheer at the rest.
He saw them. He didn't interact with them. He didn't want them to interact with you. He didn't want to spoil your very special event with your DD, nor did he want to draw attention to you and your family by pointing them out to you, you looking, they seeing that, and using that as a excuse to break NC. So he panicked, said nothing, and tried to steer you away from possible conflict.
Ideal way to handle it, ah, no. He should have told you at some point, even if it was at the end of the game when he would say something like, I didn't want to ruin your game, but my parents are here please go left so we don't have to run into them. But, if his intent was good, then maybe this can be a "this is what I would far rather have had happen vice the other" moment.
Of course, for all I know, he does this sort of dodge every time you go out together, in which place, I'll hold him while you 2x4 him.