Greatings from Canada!
Good question.
Cannot help you with NY, but certainly can with Canada.
First of all, I'd like to say it's refreshing to read people's disgust in Canada's successful conversion into a police state where the public are basically disarmed sheep. Well, except the criminals; they are armed to the teeth because laws only apply to the lawful.
Whew! So Anyway.
1) you cannot carry anything legal that will match an armed thug with a handgun - unless you happen to have a kevlar vest and you run his head over with your car.
2) but the most common thing you will come up against is a knife; or just a group of jerks looking to lay someone a beating.
for this, it's dicey but legal:
bearspray = pepperspray on steroids. it's big and unwieldley. Extremely strong pepperspray (works on a grizzly) and comes out in a fantastically powerful wall of fog. Great for 2 or more too! and has distance!
it's not terribly concealable unless in a purse or day pouch, but great for the car.
I've blasted people with this in dark parking lots trying to mug me and they thought they died and went to hell. 1 blast, then another so they breath it in and melt into a puddle. Wait a few secs so you don't breath any mist in b4 walking up and kicking their face.
pepperspray - legal for carry against dogs, make sure its not whimpy, try to get enough volume in it and 5% oc
collapsing steel baton - 21" will fit in pocket but will break bones, etc/ bearspray & one of these has been dandy for me ==these are legal, for no other reason than the bureaucrats forgot to ban them, don't bother showing canada customs it though or you'll have nothing but grief - they seem to make the laws up as they go along, so do the cops up here
a pad lock on a chain in your pocket would not be illegal.
a roll of nickels (hard to prove a weapon was used), and 'well officer, I only sprayed him with dog spray I happed to have and then only punched him once, can't help it if he is in lala land'
last but not least: the wisdom to 'keep out of it', and the physical abilities of your own body & whatever is within reach. The sidewalk can be a real manstopper when someone goes head first into it.
Canada customs and cops are [edited] that will say all of the above are illegal and would bust Mary Poppins for her umbrella. Just like new york, it's illegal to bring pepperspray or bearspray into the country but you can buy it at any sporting goods/hunting type store.
I wish I was on that Greyhound bus. I don't really know if I'd be alive or dead right now, but that [edited] would have his head caved right in with a steel police baton and bearspray. I can't believe the Canadian newspapers commended the bravery of the people on the bus for fleeing so quickly.
Britain is talking about banning all knives with points and have banned all handguns; Australia has banned all guns I think. Whadda stupid world we live in.
anyway, Enjoy your vacation and just stay out of it, take care.
sincerely, the last non-sheeple Canadian