Legal Question in Bankruptcy in California

The context of your question unclear, but there are many situations where a "right to cure" letter is not just legal but mandatory. But more information is required to fully answer your question.

Let me use California as an example. If you own a home and walked away form it during a Chapter 7, the bank must still inform you of loan modification options before it foreclosures. If the bank picked up your car for not making payments, you still have the right to bring it current and they must give you proper legal notice before auctioning off the car.

If the letter contains the proper disclaimers, there can be many circumstances where it it legal to send a "right to cure" letter.