For serious though - one reason such utterly trivial codes are common are because the "lock" is just use as a fancy way of preventing the zipper from coming undone.
Likewise, on the internet, a lot of things prompt for passwords that really don't need them. People create throwaway accounts and use them as if they were temporary anonymous sessions.
Trust me, for the luggage this is a brilliant combination. Or something like 0000. Unless I work for a 3-letter institute, I leave all luggage to their default or the usual. If someone steals a luggage, that PIN is least of the problem but everyone else in the household will if you forgot your super-smart PIN.
I have a pin lock on a shared device, that friends use occassionally. Of the three friends I have given guest access to, all three asked for their pin to be 1234, to which I said no. One had the audacity to follow up with 123456