I remember the scene on the night's ship where Shane and Cade got hold of the alien gun and Shane was trying to surrender. In that scene, the two guards doesn't seem so tall compared to Shane. A little movie error perhaps? Cause they are at the same height as Lockdown right? And he's quite tall. Taller than Bumblebee.
No, they're about the same height as the humans cause if they weren't, the humans would have no chance against them
The guards came in different sizes from what I can tell, since when Tessa was being chased, the guard chasing her was still really big, and held the ball thing in it's hand like a baseball. And the googly-eyed scrap guys and the ball scanners were bigger compared to the guards that confronted Cade, yet small compared to the ones hunting Tessa. I also want to say there was a colour difference, (like I think the small guards were more green-lit) but I'm not sure.
