I think your assumption is correct. Chalet didn't make bowls like the one posted by antiquerose. But complicating the issue is that there's a fair amount of Czech glass in Canada that also looks like Chalet, but which only had paper labels, now lost. Much of this gets attributed to Chalet, even the large, hot-worked vases designed by Jan Beranak at Skrdlovice. So without the Chalet sandblasted on the bottom, attributions have to be made cautiously. The two examples Carolyn posted are good examples of where caution is needed as they could possibly be Czech.
David
Your thoughts are the same as mine, David. The blue bowl in the eBay link that Carolyn provided looks Czech to me. I've seen many Czech pieces with bases like this. It's hard to know for sure without knowing the specific bowl.