We were wondering the same thing. This is all I have found in regards to providing them when not required, I would assume then that the rules would not apply, however when we disclosue when not required we follow the rules as if they did apply.
HUD-1 F.A.Q. #2
Q: Does voluntarily using the HUD-1 in a transaction that otherwise is not subject to RESPA result in RESPA applying to the transaction?
A: No, using the HUD-1 form does not subject a transaction to coverage under RESPA.