Ya know, after rewatching tangled and the second half of season 1? I'm actually wondering if/why no one from outside corona tried to steal the sundrop flowers after it was used on Arianna. I know they say it was destroyed but as Varian points out? Something that powerful wouldn't be just thrown away. And the stabingtons and gothel mention how valuable it is: "I was going to offer you something worth 1,000 crowns. Would've made you rich beyond your wildest dreams." -> "Fair trade, a crown for the girl with magical hair. how much do you think someone would pay to stay young and healthy forever?"
Even if they realized it wasn't destroyed, breaking into Corona's vault wasn't exactly easy, even for people who had an in.
When the crown was stolen, it wasn't in the vault. It was on display in the main hall, probably for the Lost Princess' birthday. That was a cakewalk, compared to what Rapunzel and Varian went through to get to the flower, including Varian making the truth serum and drugging enough people that someone managed to spill where the flower was being kept.











