Well, it might actually be the screen protector being correctly applied as it has the same drawing animation as the prior comic. I imagine that illustrating such a concept would be pretty difficult for something that isn't animated, so it uses something akin to an afterimage to show it being applied correctly onto the smartphones. You don't see the final still of the afterimage because at that point it's on the smartphone and therefore invisible.
Given that it was correctly applied then, the expressions in the last panel make a lot more sense as they don't seem like the "mean" kind of smiles for causing her to waste a screen protector, but more like the kind of smiles one gets when helping someone else complete a difficult task they were fretting about by distracting them enough so that they forget to be worried about it.
You're wrong though, last strip's last panel had the girl touching the bare screen with her fingers.
Oh really? Pray tell how you discerned that out of the black and white still of a comic? :EYEROLL:
I stand by what I said previously. Interpret the comic how you wish at your own peril.
Uh, maybe because you can see the bottom of the backing card at a slant to the protector? The protector being at an odd angle with the speech bubble "Stick" telling you it got STUCK in that off-angle position?
Same with Naomi in the previous strip. She's touching the unprotected part of the screen, because the protector is ALSO slanted thanks to Kay interrupting Alisa.