#but by gods this protective nature will return with vicious force when Tarn becomes a threat

[transingthoseformers]

Also just imagine when Megatron's coding calms down and stops assuming everything is a threat that needs to be met with immediate lethal force and finally leaves his quarters. Every bot he meets has to basically be like **P A N I C** while trying to act normal. Not at all paying attention to the chirping little blob on your pauldron with some very telling finials. Never seen anything even remotely close to that in all my functioning so please don't tear my head off Lord Megatron.

And yes I like to think sparkling rides on his shoulder. Maybe special baby magnets? Like the grasping reflex in babies.

Special magic baby magnetic servos

Logically, there's probably an instinctive reason why Cybertronian coding would necessitate this murderous intent to anything that could be harmful to sparkling (ie predacons to ancient transformers)

I could also see so much casually cradling Silverlight to Megatron's (and eventually Optimus's) chassis. That sparkling will probably not touch the ground until a way a lot later on, it's too fragile and there's too much that could happen with big mecha walking around.