I've never held security clearance, but every job I've held has had some sort of need to know or confidential information sort of policy-espeically if you end up in charge of other people. There are always consequences for such things if violated to one degree or another. Or sometimes people will be let off lightly.
I think it's important to take security and info that could harm or jeopardize the safety of others seriously and to probably follow procedures to do so-unless the procedures harm someone. I think not having consequences creates an environment in which people become lazy about it and eventually someone gets harmed.
I do think it's become clear that many politicians need regular help with security because they either are ignorant or make alot of mistakes, deliberately mess up or leak, or don't care to do it right.
Regular training and clear consequences would help. Many companies regularly do so.
In Clinton's case I believe no deliberate mishandling was proven after investigating.
Think that will be the case for Donald Trump? I doubt it.
I do not think the cases are equal.