Kate Hudson Shows Lance's Kids Who's Boss

Kate Hudson spent 4th of July weekend hanging out with the Armstrong's as if she were part of the family already.  Except it's still unclear whether she would fit in as a big sister or a stepmom to Lance's kids. 

As you can see, Kate isn't exactly rocking the mom thing with all that much authority.  In fact, Kate seems a little more like Lance's daughter's bitch than her boss.

It can't be easy being a stepmom, dude.  You gotta be nice to the kids so they like you, but if you're too nice they'll walk all over you. 

Pictures of Kate and Lance bringing Luke, Isabelle and Grace to tennis camp below...