Quantity is often queried for Unit just to see if it has a dimension. Ask Quantity directly using isDimensionless() method and modify that method not to care about Quantity value validity; no user was ever asking for value validity.
Quantity is often queried for Unit just to see if it has a dimension. Ask Quantity directly using isDimensionless() method and modify that method not to care about Quantity value validity; no user was ever asking for value validity.