Obstruction or not?

[JefferMC]

Dang, Matt, were you at my daughter's game Saturday?

The exact thing happened to her running to first, except that she didn't slow down a whole lot, and tried to step around the first baseman while remaining in the lane. She brushed by the (ball-containing) glove before stepping on 1B. The BU didn't see the tag (or apparently care about the obstruction, making no DDB sign or saying "obstruction"), calling her "safe" at first.

The opposing coach asked the BU to go for help. He tried to give it to the plate ump by pointing. The PU would (rightfully) have none of that, he walked up and they had a conference near first base. At the end of the conference the BU impatiently waited for the PU to return to the plate and turn around (I say impatiently because he started to make the out hammer about 3 or 4 times before the PU got there) then pointed at the PU, made the hammer and called out. That, I thought, was strange behavior.

Our 1B coach didn't go for an obtruction call, though for the life of me, I don't know why not. (Actually, he probably just doesn't understand obstruction...)