Knowing how House of Blues operates, I can say that they probably gave the merchandise guy very strict rules about getting the merch table down by the time the show ended, because HOB tries to shove everyone out of there as quickly as possibly once the last note is played, most particularly in the case of an all ages show. Plus, security probably gets on their cases about that small area getting too congested with people waiting in line....as discussed before in this forum, HOB security and staff tend to be a bit overbearing....
I can't understand why they didn't just let them set up the merch back in the coat check area. It's much much more convenient and spacious there.
And as for the lack of merch per show thing, unfortunately that's a problem thats always going to exist. Unless a band seriously overstocks their merch at the beginning of a tour (and even sometimes that doesnt work due to surprising demand) they have to allocate their stuff per show. On the BWP tour, they didnt do that, and what happened was that little more than halfway through the tour they ran out of certain shirts, and then you had people screaming about how Opeth didn't have any shirts when they came to their town. It's a really tricky situation that unfortunately tends to leave someone unsatisfied at some point. Hopefully on the full length U.S. tour, they will have more than enough merch to go around. I myself didnt get a hoodie because they sold out....hopefully next time.