I am not 100% of what stock limits are, but inside the shop they are allowed a max of 500 grams of product. The police raid and check this, all product is weighed. I think with stock limits in pace it also means it is difficult for planning. If someone has the best gear around, and your stick is full, realistically you cannot buy it....it's all a bit of a Grey Area...hence why they called my favourite coffeeshop the Grey Area...
They are allowed to sell you max 5 grams, so if you get caught in the shop with more it can look suspicious. I have never heard of anyone getting done for having more, but there's always a first.
And yeh, you see like tourists with about 10 bags of 1 gram deals...makes me laugh because 50% of it is probably the same haha.