I agree with everything said above. I've had many clients tell me "the investor says I have to ____" (insert incorrect regulatory issue here). When it comes to overkill, you may have to play by their rules. For instance, many investors require a RofR when a construction converts to permanent financing even though this is clearly a Residential Mortgage Transaction which is exempt. However, as raitchjay said, if you want to sell loans to them, you plan by their rules.
However, I've also seen where investors require too much money to be in an escrow or require a bank to collect for escrow items (at closing) that will fall within the escrow account computation year. In this case, the investor is wrong and making the closing bank perform an illegal practice. As Truffle said, that's when I call the investor's compliance department. And, as Truffle said, I usually win. In fact, what we find is the compliance officer/department has not endorsed or was not aware this was going on and is glad to hear we are reporting this practice.