i think by now, autobots should have their own base, like in the G1..do you need any disguise at home? i dun think so,
why not think this way? dinobots came to earth since very very very long time ago & found out by autobots just after 1st movie, frozen somewhere like megatron before. they knoe this group is the most dangerous n brutal n decided to keep em in "freezer"..later on in 2nd movie, serve as secret weapon to fight with the fallen..
just my 2 cent