Besides the emotional significance for the ex, could it be the common spitball strategy? Kids in school quickly learn, throw enough spitballs at the wall and odds are something will stick. (And with enough of them flying, the teacher will get distracted and be unable to pick out the instigator.) If ex made just one claim, the answer might be a simple No. But make many claims and the odds of at least something being granted, even partially, like throwing a bone, probably go up. And that would be a Pavlovian 'reward' outshining all the other claims that were denied.
I am not quite sure what she is doing... . all I can say is that she is getting increasingly snarky in her emails to my DH any time he has to inform her of something (and he avoids it as much as possible). For instance, he invited her to a feedback session to discuss their son's testing results (she didn't want him tested despite the school and his counselor's recommendation). She initially did not respond for days, but when he later sent her the actual location, she wrote back that she would not be able to go and "we will be sending a legal request for records." Uh... . or he could just give you the report? He wrote back, "No worries... . I will send you the report."
She can't stand to be in the same auditorium as us during a kid's performance and huffed herself out of there... . we were not even that close to her.
So I guess her increased irritability is a sign that she the court date being moved is making her mad for whatever reason.
