
Part of the reason Elsa kept trying to be the perfect heir for so long is because she believes that Anna is a terrible judge of character and would get eaten alive in political situations.
Because if her sister likes a monster like her, God knows who else she might like.
If you let Elsa rely on you once, she will try very very hard not to rely on you again.
But she doesn’t have that many people to turn to.
So chances are if you’re kind to her and she thinks you can stabilize her, she’ll use you for that.
Elsa’s triggers;
Touch that she doesn’t initiate or expect.
Red on white.
Anything that she can reference back to her hurting Anna. ( Honestly sometimes the white in Anna’s hair can be triggering. It just depends on the situation )

Fewer things are more triggering to Elsa than when the colors red and white combine– or even if it’s a light blue. It’s even worse if it’s actually blood or anything that looks remotely close to blood on snow.
In this drabble you can see why that is.
But basically hurting people is Elsa’s biggest fear. She doesn't just worry about freezing their insides. She’s very aware that ice can cause scrapes and bruises and in the worst sorts of situations involving her– impalement.
Basically this is an actual trigger for Elsa. She will shut down, become upset or irritable, try to get out of whatever interaction is going on, etc, etc.
Elsa very rarely gives a compliment that isn’t attached to an affectionate insult or something of that nature. If you receive a super sincere genuine one she is either upset or you’ve reached an almost unattainable level of importance. (Ex: Anna would get them most frequently )
While a very kind and benevolent ruler in Arendelle, Elsa can be quite brutal in politics. ( or business in modern )
If she feels you are plotting against her or her country, she will preemptively confront you. You will be cut out of trade and Arendelle will boycott your goods.
Elsa knows the best way to hurt a diplomat is his coin purse and this response saves more lives than a war would.
She will raise her bans under the conditions of complete confessions and apologies. Sending gifts or arguing with her will get you absolutely nowhere.
Elsa’s powers are not inheritable or hereditary. She was born with them and we aren’t quite sure why. But magic seems very rare and.. really almost unpredictable in both Tangled and Frozen. I doubt it would suddenly become passed on.

I do imagine that even after Elsa has returned to being Arendelle’s Queen, countries would send assassins. People as powerful as Elsa don’t just get left alone. The world is always afraid of what they may do on a whim.
That said…
Elsa refuses to have guards. She believes there is no point in people losing their lives to protect her when she is perfectly capable of protecting herself– and protecting herself better than any guard could.