The reason Martians don't appear to have any locks is because their society is just that regimented
With the exception of Dropo, whom everyone treats like a mental deficient, nobody even thinks about stepping out of line by trying to go through doors that aren't theirs. Therefore, why bother with locks?- Maybe the Martians are related to the Kazons from Star Trek? They're so hard-wired into obedience that you can make an inescapable prison for them by drawing a line on the ground and telling them not to cross it.
Santa actually did try to come to Mars
But the ancient Martians kept shooting down his sleigh The Martians are cyborgs, somewhat
Their helmets are basically fused to their heads and the source of their enhanced ability to learn and other sensory abilities. They primarily learn by sitting around a gizmo that beams knowledge into their heads. They may even be artificially telepathic, and their belts are part of this system. This is why Chochem the ancient Martian sage doesn't wear a helmet, he's so ancient and wise that he knows everything and doesn't need a helmet anymore. Kimar is a Reasonable Authority Figure and a loving father because of Chochem
Kimar regularly visits the old sage, and the sage is aware that the regular Martian Way is becoming stifling and self-destructive. Kimar respects Chochem highly and is generally influenced into taking a more measured approach to things rather than the usual blowing up of stuff. This really gets Voldar's goat and the whole Santa thing was when it all came to a head and Martian society changed for the better. Dropo is either Kimar's household servant or dopey brother
Hence why he seems to live at Kimar & Momar's home and hasn't been jailed or executed despite being an incompetent buffoon in a society of highly regimented Proud Warrior Race Guys. It also helps that Kimar is a Reasonable Authority Figure and rather lenient by Martian standards. Mars is very Male-Centric and has a system of naming conventions
Since it is... of course... MARS... and why the mother Martian, Momar ('Mom-Martian') isn't referred to as a Queen or "Queemar". Mars only allows Kings as rulers and wives of Kings are simply given the honorific "Lady". The suffix, "Mar" is also only reserved for the Royal Family. Medium-rank Martians get names ending in "Dar". Lower-rank Martians and average-citizen Martians get simplistic names like "Dropo", "Shim" and "Stobo".