Unless someone accurately tests and proves that there's something, magical about a 28mm tire over a 30mm, the simple answer is to change to 30. My latest Pirelli P-Zero ROAD TLR tires in 30mm aren't 2mm wider than the 28mm RACE version that I use on the front. I agree that all wheel brands should align their recommendations with ISO or ETRTO to avoid lawsuits, but if there are really tires being blown off at recommended pressures and size combinations, then there's likely to be lawsuits, particularly if there's enough money in it to be worthwhile for the ambulance chasing attorneys.
I'm still running 28mm front on 25mm hookless at 52-55 psi and I've tested at 85, so I'm not worried.