The fact is this weak economy is also taking its toll in the Chinatown businesses. Shop owners have enough time to look around how others are doing, some get seriously jealous if someone else is has more customers! ..........and suddenly they remember laws and rules which have never been enforced before that say:
"You have to consume your drink wherever you've purchased it!" It's the stall owner who has to make sure everything is in order. Anyone who doesn't follow that rule will be reported!
It's as simple as that!
By the way, you can get beer for reasonable prices right next to Erich in the food street and even enjoy Erich's sausages there.
Fruit juices from Stanley next door you can drink at Erich's. No problem at all!
However no rule disallows to bring your own, just cover up, nosy neighbours might watch!