Accusations of abuse seem pretty rational to me in a custody battle. It's one of the best ways to get custody. Come up with some 'witnesses', trick the kid into testifying on your side. Have the attorney write up the sob story and blindside the other partner so they're left defenseless. Bonus points if you can get a restraining order in the process so custody is lost and continuity is maintained by continuing the custody terms of the restraining order -- also a good way to destroy means of defense as in some states a spouse has their firearm rights suspended during the order.
it is actually not. Courts tend to punish those if they don't believe them - accusing partner of abuse is fairly often how you get less custody.
Restraining orders are not easy to get either. It can take quite a lot of fight even in cases where actual stalking and threats of violence are going on.
You're the judge and I'm a 'battered wife.' In this fiction: I self-harm myself (claim it was the husband), come up with a terrible and fairly convincing but unverifiable story of abuse and be sure to mention to you my husband has several guns and has threatened me and the kids with them. Do you choose to issue a restraining order, or do you roll the dice and hope nothing bad happens?
"Going in with a co-operative mindset (at least until the other party demonstrates they are not) should be win-win."
Do you have a source for this? In my state, and many others, temporary protection from abuse orders against spouses are very easy to get just by saying the right things without any real evidence. Those stay in effect for a couple of weeks until a hearing. Then it's difficult to get them overturned unless you have physical proof because the course want to "err on the side of caution".
There are divorce lawyers who actually recommend filing false protection orders during divorce, for the very reasons stated by the previous commenter. It's well known amongst divorce attorneys that some in their profession do this. There is generally no punishment for those attorneys since you can't prove their involvement easily, nor for the false filer in many cases. After all, if your spouse is a felon (perjury) the courts will likely make you pay more in child support and alimony due to their limited earning potential.
Things can vary by state. However, I don't know of any state that isn't going to take sides (literally why the judge/master is there if it comes to a trial). Courts are generally not going to ignore any claims about abuse.
This is a well known issue that may be more prevalent in some states than others, but is certainly a national issue.