Visible crew/equipment: In the desert, Helmet asks the guys "combing" the desert if they've found anything. The camera crew is reflected in the helmet of the guy that says "we ain't found shit."
Revealing mistake: When Vespa starts shooting at the guards on the platform, the one on the end flips over when shot, and you can see him bend over after he's shot to prepare himself for the stunt.
Continuity mistake: As the shaving guard falls, he gets shaving cream on Lonestar's right jacket arm. In the next shot Lonestar reaches down to grab the badge and that same arm comes into view and it is completely clean. There isn't enough time between shots for him to have wiped it off.
Continuity mistake: When Dark Helmet takes the ring from Lonestar, he throws down into a grate. Later, when Megamaid explodes and Lonestar and company cheer, for a brief second, you can see the ring back on his finger.
Answer: It also might stand to reason that the very fact that Druidia has a shield is what makes it viable. It almost creates a docking port for Mega Maid who was presumably designed for that very purpose. After all, what other purpose could a space maid with a vacuum possibly have?