My siblings are requesting an accounting of my mom's finances - because I am the POA - but my mom is still perfectly capable of making her own financial decisions and does not want this information shared. She has overseen everything, but, for example, does not go to the store and make the actual transaction - I do that for her.
Would a court require an accounting if she doesn't want her info shared?
A POA is a tool. It gives the person assigned the ability to handle an incompetent persons finances and medical wishes if you have a Medical POA. The only thing your siblings could do was go to a lawyer and ask for an accounting if you personally were handling Moms finances. They can't ask for an accounting from Mom if she is competent.
Are your siblings afraid she will spend "their" inheritance? Mom owes them nothing. She can spend everything if she wants. Its her money not theirs. She has no obligation to leave them anything. Its her money, she worked for it.
The only thing I suggest is if you run errands that you pay for and then she reimburses you by check, keep the receipts with the check no. on them. You don't want to be accused of Mom "giving you money".
It would be a good thing to have the lawyer who drew up the POA explain to you how it works and your responsibilities once Mom becomes incompetent.
https://www.agingcare.com/articles/why-a-letter-of-competency-should-be-part-of-every-seniors-legal-file-441176.htm
Tell them when they have all sent those details to your mom, you will ask her if she would like to do the same for them.
I think Mom chose the right person to be her POA. Too many times on this forum you read how a child abused their POA.
I read my state's statute about it, and it looks like for them to actually receive anything from a court, they would have to prove that our mom is incompetent, so it doesn't look like it would go anywhere.