I carry a grinder with me ON EVERY TRIP. I have a hand grinder in my 22" roller (CARRY ON ONLY) every trip of the last 4+ years. Before that, I used the two blade one you're talking about (but blade grinders like this heat up beans as they are ground and change the taste, so now I mostly only use a burr (plate) grinder type).
I've never had any TSA even ask about it, look at it, anything.