From: Rabbi Moshe Sofer
To: Tritsch
A young man placed a small wooden barrel hoop worth far less than a perutah on a girl's finger and declared betrothal, claiming it was a joke; the girl said she did not understand him. The Chasam Sofer finds multiple convergent grounds for leniency — the item's value was below a perutah, it was taken without permission but as a worthless object constitutes no legal theft, and the circumstances corroborate the claim of jest — and rules the woman does not require a get, deferring the final practical ruling to the local Av Beis Din.
Source: Shu"t Chasam Sofer EH I §85