I am confused with the extreme fragility of the bag of holding in conjunction with dramatic consequences of its destruction.
According to DMG (5th Ed.), if the bag is overloaded, pierced, or torn, it ruptures and is destroyed, and its contents are scattered in the Astral Plane. But I found no reason why to pierce or tear a bag of holding would be more difficult than an ordinary bag. Thus, if a character carries a bag of holding, every street boy with a knife may easy deprive him of the bag and 500 pounds of valuable belongings. In fact, not even a boy, but any curious magpie with a sharp beak may wipe out the bulk of character’s stuff in a moment.
A bag of holding usually is not a museum piece that is kept in a secure depository, but something that a character carries on his person during all adventures, in unfamiliar and dangerous environment, at the time of battle, etc. An item that can be damaged both so easily and so irrevocably is hardly an appropriate equipment for an adventurer. So I wonder why does this sort of item exist at all and why a character will run a risk of using it.
Or did I miss something?
DMG pg. 141 Magic Item Resilience states that:
"Most magic items are objects of extraordinary artisianship. Thanks to a combination of careful crafting and magical reinforcement, a magic item is at least as durable as a nonmagical item of its kind. Most magic items, other than potions and scrolls, have resistance to all damage..."
The last part is about artifacts and is irrelevant here. But it's suggesting that the Bag of Holding would have resistance to all damage, so it would take twice as much damage to pierce a hole in it than in an ordinary bag. That still isn't a lot of damage, but it's better protection than nothing.
The fragility implied by the description is likely just a legacy inclusion - no real need to remove it because it is always the DM that decides if such a thing would happen, and the general rules regarding worn and carried objects is that they are pretty close to indestructable since, as an example, carrying it is the difference between a sheet of gasoline soaked paper going up in flames within the area of a fireball or it being entirely unharmed even if the fireball kills the character holding the fire hazard, and a little nod to tradition made by leaving it in.
It's not the game's way of encouraging the DM to worry about the bag being ripped or pierced - just something which happens to be true, should anything come along that results in such an occurance (like players intentionally tyring to do those things).
Traditionally, the concern with piercing came from storing sharp pointy object *inside* the bag....
If you decide that a bag of holding IS fragile, the cutpurse who pokes a hole in it will get a real surprise when 500 pounds of gear falls out and lands on his foot and this bag keeps disgorging gold coins like a Las Vegas slot machine hitting the jackpot. 
Not to mention the half-dozen proficient adventurers who now are offering him their total and undivided attention. 
BRJN wrote:
Devils-Advocate wrote:
You could always put the bag of holding inside a normal back pack if your worried about it. And if your extra worried you could put it in a normal back pack after you wrap it in a blanket.
BRJN wrote: