WEll, I think you are bound to a point. There is an exception in 229.13:
(4) For the purposes of this section, a ``reasonable period'' is an extension of up to one business day for checks described in Sec. 229.10(c)(1)(vi), five business days for checks described in Sec. 229.12(b) (1) through (4), and six business days for checks described in Sec. 229.12(c) (1) and (2) or Sec. 229.12(f). A longer extension may be reasonable, but the bank has the burden of so establishing.
If you find out the check is fraudulent, you can extend the hold. However, if you know up front it's fraudlent, I'd refuse or send for collection if the customner insists.
My opinion only. Not legal advice.
Say you'll haunt me - Stone Sour