Why do harrods staff ask customers to hand carry their backpacks?

Question

Why do harrods staff ask customers to hand carry their backpacks?

Answer 1

For safety.  It's easy to knock something over if you carry it on your back.

Answer 2

i can only assume so that no one else can put anything into their back packs without them knowing or working with them and putting stuff in to steal

Answer 3

To avoid damage to the displays if you turn and are careless of your backpack.

Yes, I know this could happen with a shoulder bag too....I guess they see backpacks as the biggest risk (and they lost too many arguments with ladies carrying shoulder bags!!)