You could explain that no one can see an album unless they're signed into KP. Which means they've paid for an account and been verified and such so there probably aren't any creepy stalker-type people on here. Also, seeing a picture of someone doesn't really make it very easy to find them... it doesn't tell their address or anything.
I don't know your mom, but if she's going to launch into a speech about Internet safety, she probably will anyway. :P