It will only capture v1 and also reserve a larger stack space in case the new computation needs it, where the stackless equivalent does not require this.
> Without explicitly forking v2 will be captured, but then it is a completely different program with different semantics and it doesn't make sense to say that it captures more
It doesn't have different semantics just because v1 changes ones space behaviour and not the other's.
I'm not interested in Turing tarpit arguments that one can be made equivalent to the other. As I've already said, the point is what existing systems encourage what sort of program architectures and what allocation behaviour naturally follows. It's long been evident that stackless abstractions clearly must capture strictly less state at any given time.