This year our team got a 3’ x 5’ flag made, but in Canada it is not common practice to have them waved on the field pre-match as is done in the USA.
What are the guidelines we should be following to join this party?
how should the flag be identified?
how long should the pole be?
any other considerations
Thanks!
There are no real rules to this. I have seen long flag poles, and I have seen short. We use a broomstick length of carbon fiber for our flag poles.
Your flag should have your team number or logo on it and you bring it to the field with you when you play. They usually have someone helping coordinate that so the MC knows whose flag is whose.
Try to keep the pole light but strong enough to not break. A 4.5 to 6 ft. Pole would be about right.
Have your technician ready to take the flag and return it to your cart.
Place the flag unrolled on the charge station with the holding end pointing to mid field. Lined up with your drivers position.
For a pole, you can get hockey sticks made out of carbon fiber.
PVC flagpoles work well, and might be a tad friendlier in terms of budget. Feel free to paint it or wrap it in your favorite color tape.
If you do make a flag, I would also recommend making a flag holder on your robot cart so that the drive team members don’t have to carry it around everywhere. Plus it helps keep the flag clean since it would likely end up lying on the floor otherwise!
PVC, carbon fiber, anything like that will work fine.
Something that the NE district did for their division flags this year was they gaff taped it to a broom handle and that worked fine, so you could try one of those as well.
Or you know, you can just use a loaf of bread 
If If you’re looking for something quick, ask around in the team to borrow an 8’ paint pole. It’s light, collapsible, and the right length for a 3x5.
Some may think Scott is joking here, but it’s a serious and great answer (especially for us Canadian’s).
2386 used to frequently attend regionals in the US, and we’d regularly bring a Canadian flag mounted to a hockey stick as our “team flag”. It was important to us as a team to be representing Canada wherever we went, and what better way than to incorporate hockey sticks into the aesthetic!?! It’s also pretty easy to find old hockey sticks up here that can be donated to the team (I remember one year getting a large donation of carbon fiber sticks that were deemed unusable/broken by a local hockey league).
For OP, the thread linked above by @leo-les is a great and modern guide to most of your questions, I’d highly recommend reading through that.
Not a guideline but something to remember - make sure that if you have any students waving it in the stands (or wherever) you let them know not to accidentally hit anyone in the face. Waving a flag carefully is more important than one might initially think. We’ve had a few near misses!
I have to assume there’s a hotly contested Endian style debate over having the blade at the top or bottom of the flag?
“Debate”? There is no debating here; The blade OBVIOUSLY goes at the top of the flag 
I have to politely agree. Always goes at the top.
Ah, but same direction as flag or away from it? Surely we can get Canadians to disagree on something!
I don’t know. They’re such polite and agreeable people.
We had similar issues with the flags in the stands whenever we would put it away after a match, we would always hit someone’s knees. We finally just cut it on the bandsaw by a foot or so.
Teams should be reasonable with their flags. I heard a story of an Emcee dislocating his shoulder waving around a supersized team flag. That is unacceptable.
Fun fact I wrote my flag post from the gym because I realized my shouldee was in more pain than it should have been. Partially on me for not sufficiently stretching!
Or here’s a solution… Just wear safety glasses in the stands! That will fix the problem. (Wearing safety glasses makes you impervious to any harm)