Not in the instances that I'm referring to. If it's a completely unrelated subject within a thread, I've seen instances of a new thread being created and I fully support that. Can be a fine line as you intimated in your OP.
One issue I have is when there's already been quite a bit of discussion on a particular topic within a thread and a new thread is subsequently created. It then makes for similar discussion in two places. A little scattered and chaotic when it occurs IMO.
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Sam Reinhart captained #Canada's gold-medal teams at '12 Ivan Hlinka Memorial & '13 Under-18 World Championship (@SabresPR) #Sabres2014Draft