Robots in Disguise????

How come in the movie Bumblebee, can turn side ways and change into a different shell of a car, but in the cartoons the only time they change there look is when teletran 1 sends out, the little drone thing, to scan vehicles in the normal world.
But from then on they all decide to pretty much stay the same all the time.
you'd think if they were really robots in disguise, they might want to change there disguise once in a while to fool the enemy.
But from then on they all decide to pretty much stay the same all the time.
you'd think if they were really robots in disguise, they might want to change there disguise once in a while to fool the enemy.