since she's surely aware they can change the rules at any time.

But she is forcing them to actually come up with some rules, in public now rather than play around and make up rules as they go along later. They'll have to either put forward some rules now that the public can see and hear and there'll be a lot of public scrutiny of them or get blamed for holding up the process. And if come up with rules now and later change them, that will also be very public and obvious. I think it will be harder (not impossible, but not as easy) to change them once agreed to since they'd have to convince the Romneys and Murkowskis to agree to a revision, which won't be a breeze.

I think their plan was to play hide the ball, get the Articles and then make things up as they went along. Pelosi called the vote.