RIAA lawyers have no qualms about requesting a continuance when it suits their own purposes. In fact it's one of their favorite tactics to use whenever someone refuses to settle and instead insists on a trial.
Of course those continuances serve to cost the defendants money in legal fees (responding to RIAA motions).
Given the evidence against Jammie Thomas it seems unlikely the RIAA could have a stronger case. So why would they be opposed to her mounting the best defense possible?
It's pretty clear what worries them most is an opponent who understands the law. To date they have managed to avoid any judgement on the constitutionality of damage awards which amount to thousands or even millions of times the actual damages proven.
RIAA lawyers claim previous caselaw, which seems to say exactly that, isn't relevant because it doesn't address the statutory minimum, but rather actual damages. But they don't exactly have a stellar track record when it comes to legal theories.
It was another of their controversial arguments, that sharing files is infringement whether anyone downloads them or not, which led to Ms Thomas losing the case initially, and its conflict with relevant precedents which won her a new trial.