When ammunition exceeds SAAMI specifications, ammo makers expose themselves to all manner of unpleasant civil litigation, unfavorable publicity, etc. So, if you can find even a single example of a well known manufacturer loading ammo in excees of SAAMI specs, please share.
I would opine that not following an accepted (but not required) voluntary industry standard wouldn't specifically "open" anyone up to civil litigation... at least without first mentioning that anyone can unleash civil litigation at will simply by having a lawyer, some money, some time, energy and a frothing desire to sue.
However, it could be argued that
Buffalo Bore does fit the mold of what you are asking for if you consider that they package some of their ammo with +P notations that according to SAAMI, do not actually exist.
I've said it before and I will reiterate...
Something like ".380 Auto+P" (marketed by Buffalo Bore) is loaded to the same
official industry standard as "380 T-Rex Slayer" which is my corny way of saying that it's nonsensical or that it follows NO SUCH STANDARD as one simply doesn't exist. Thus, a .380 Auto+P marketed by Buffalo Bore (or marketed by Bubba's Discount ammo & buttcrack cream) might be both loaded to 54,500 PSI or to 23,750 PSI or anywhere in between or higher... because
no industry standard exists for .380 Auto+P.
haha, *EDIT* to add that I see
Cheapshooter already captured my point and did it more cleanly than I did.