Theft and the fact they tend to be in locations (like street corners) where cars may crash into them.
There's a really OG mailbox in my town, it's bent a full 10° towards the house it stands in front of, has classification as a historical relic and all, that has been run into by cars at least 3 times per year since cars were around.
It is still standing.
At one point (around when it got its classification), they put safety poles around it.
Until they got removed, they ended up getting replaced every year because they were all bent to hell from new accidents.
In the US, residential mailboxes are actually suppose to be made to give away when hit by a car. Even the large brick ones in the south are designed to just fall over on a hit.
It's a safety feature for the dumbass drivers hitting mailboxes.
That works, car hits it and pushes concrete bucket. Their car is fucked, your mailbox just need to be put back in place, postmaster is happy. Win win win situation.
Yeah lol, on one of my old phones I have pictures of my mailbox, broken pieces of bucket, and several chunks of honda scattered 30 yards down the street. No more bucket, but the concrete was just fine. I had to straighten the pole a little, but it still stands.
I'd argue that the people running into mailboxes with their cars are a danger to pedestrians, cyclists and other drivers so it is best for them to get a proper dent and learn to be more careful.
if they drive at a speed where hitting a mailbox is deadly, then they are at least double over the speed limit, or the speed limits in the US are insane in residential areas.
I'd imagine that's a benefit, but the design was probably for structural integrity. Last thing you want is for someone to lean on it, tipping over, and then rolling down a hill or something.
When the IRA was in full offensive mode they would call in bombings to the authorities to give them enough time to evacuate areas before the bombs detonated. They wanted publicity & destruction but not injuries or deaths. By making the bombings more of a nuisance than a threat to life they figured they would avoid losing a lot of public support for their cause. They were against the British government, not British citizens.