At worst, I think a cop might give you some grief about a large knife. Otherwise, if you act like a normal, decent human being, the most you'll get is an odd look. (Of course, there are always wannabes and personnel with chips on shoulders, but every profession has those.)

Re judges, a cop brings a case like this into a courtroom where a judge has a packed calendar, the man or woman in black may well get PO'd and bounce it most rapidly.

Re dogs ... they may be less than rare in large cities, but the cost of acquiring, training, housing, paying or rewarding comp-time to their handlers will mean they'll not likely become common in small-town American. A lof of small departments still can't afford (or won't spring for) narcotics-trained dogs, which are much more readily available.

Course, if the demand goes high enough for explosive-trained dogs, the market will supply them. It's no harder to train the right dog (nose, drive, intelligence, desire to please) for explosives than it is for drugs, termites, fire accelerants, whatever.

In short, i think with or without a dog, most cops have enough real things to worry about w/o hassling Joe Average who happens to carry some survival gear.