Dunno why SP doesn't put limits...
It's simple: it wasn't obvious before we pushed it, otherwise Bill & co in purchasing would have applied the caps. Moreover, given the sales patterns, it wouldn't have made a tremendous difference. Those 200 tins were split 32 ways, of which exactly two orders were greater than 12 tins each, and none were more than 50. The reason it disappeared quickly is because of a) higher than normal uptake from the notification list, b) quantity distribution clustered about 5, instead of about 2, which would have been more typical for a product with Dark Flake's historical sales characteristics.
This suggests that lots of people were a little nervous about the blend and probably bought about twice what they normally would have with something like this coming back in.
If we apply limits and it's not necessary, it's needlessly inconvenient to those who want 10 or 15 or 20 tins, so we try to only do it when we have a reasonable expectation (backed with a lot of data) that it'll be an issue. Keep in mind that, in hindsight, everything is obvious. Similarly, in hindsight, the Presbyterian limits were probably--barely--unnecessary. We're predicting the future with limited, imperfect information.
Regardless, we've been told that remainder of our order is shipping soon, so we expect that this is a temporary situation.
Sykes