I assume they're more strict,. When I send packages they tend to arrive fast. When packages are sent here, it's a whole different story. But it also depends what country it comes from. When a package is sent, a person has to present an ID so it's on record who sent it. And you have to say what's in the package. Then they have scanners and the likes. So if there are inconsistencies they open them up. Sometimes they also open some randomly.
Some of the packages I got in the past were opened by customs (they label it with a sticker when they do). Some haven't. Kinda varies.
Jokes aside, the mail here sucks so bad I wouldn't be surprised.
My friend ordered a pair of leather boots once. They arrived like a month late, in a plastic bag, covered in mold. There was a paper attached saying that the package got destroyed by water damage while it was being held in their warehouse. So have your moldy boots and a delightful ******* day lol