Guess you're right. The point in "hanging around" on the node is that she would later (quite later, that is; when the ambush was all set up and Tachikoma jumped in the node) edit the accounts privelege lists on the node in order for the assigned driver to have his access blocked - and, in doing so, she would mantain a subscription on the node (otherwise, she would have to hack into it again, which is more likely to be discovered than just being there idly doing nothing and concealed by the Stealth program; strange, but that's how Shadowrun Matrix works by RAW).