"Is it possible that Kosta Boda et al are OK with compromising their brands by selling seconds without any obvious indication? Or perhaps they won't release even seconds that aren't up to a very high standard."
(i don't know how to make quotes properly, it seems)
Yes, KostaBoda (and all other glassworks in the area) are selling seconds at their own "outlets" (ie the shops at the factory grounds) - in fact, it is "understood" that *all* objects sold at the "outlets" are seconds. In Kosta, they have a (small-ish) section in the shop for "firsts", indicated by a sign at the entrance of that section.
Even seconds always have a sticker, but stickers can easily get lost.
Not all of the local "outlets", hm, "spell out" that their goods at the grounds are seconds, but somehow "everybody" knows that. The first sign is that the pieces are not signed. Back to Kosta, some (what do you call it? tea lights?) Snowball have a sandblasted "Kosta" at the bottom, but not all. They usually are sold at the same price, and they usually are made with the same moulds - thus, Snowball is not a typical product sold in first/second selection. All the same, one could have bought several Snowball and got half of them "signed", half not.
Regarding BW Brains I do not really know anything - but I can speculate... Years ago, the new owner (2005, New Wave Group) declared that, to make things viable, 80% of the production had to be outsourced. Understand that *I* have no idea of what, when or how - anyway, when I go to the Kosta factory outlet, i find many objects that are made "elswhere" (Bulgaria, Turkey, Slovenia, China just to mention some), because it is printed on the boxes. I remember seeing "made in Germany" ages ago (>15 years? before New wave Group, anyway) on the Orrefors brand.
(In my (not so humble) opinion "Brains" is quite a simple product, technically, ... who knows?)
So, back to your question:
"Is it possible that Kosta Boda et al are OK with compromising their brands by selling seconds without any obvious indication? Or perhaps they won't release even seconds that aren't up to a very high standard."
my answer would be: there *is* an indication: the lack of a signature.
Probably most seconds would not have faults that (us?) ordinary ppl can easily see. It takes a skilled worker ( what I, for the lack of proper terminology, called "an expert checker (working at the glassworks)" below) to "separate the wheat from the chaff" - so much so that there is a saying (here, at the heart of the Kingdom of Crystal) that one should always have an expert cutter/engraver to do the checking, 'cos they would know which pieces could go from "seconds" to "firsts" if sent to the cutting/engraving shop...
Oh, and the forever recurring: NO, signatures are NOT acually performed by the artists themselves. Signatures are valid all the same.