Upon reading this, the 1st thing that popped in my mind is where did you get the knife from &/or where do you live? If you're in the U.S. & the co. you got it from is also in the U.S., then yes, that's odd. If you bought it at a brick & mortar store, I would've returned it for another. However, getting a tool to fix it is certainly a solution.
As for the "travesty" that the Umnum doesn't come with a tool, like the Sebs, is that really that big of an issue?
Striders need (Well, it's easier with it, anyways) a tool to undo the pivot, but I don't recall reading a bunch of complaints that they don't include the tool with their knife.
I think people got spoiled with the Seb. Yes, it's nice that the Seb comes with a tool that just about anyone with other knives would have, but to have to spend a few $ for it isn't really that big of a deal, is it?
I'll agree with "Big Mark" here in that, while I haven't spent anywhere near the $ he has, I've had some customs that had "issues". Never mind not coming with a tool.
I think the "problem" here is that CRK set the bar pretty high in what to expect when you buy one of their knives. Then they come out with the Umnum & no tool, especially when it's a needed tool, not something most people already have.
For the OP, do you live in Canada or got the knife from a Canadian store? If not, sorry you had to go through this. I've only tried 1 Umnum (The one I have), but it was/is smooth from the get go.