hyper_one
Yea you are right. You CAN buy Canadian lottery tickets from here and take THEM back into the USA but you CANNOT buy American lottery tickets and return to Canada with them THEN go back into the USA with same.
Apparently, there's a law on the US books about those regulations and my reasons for saying that its because when that PB was $!.6 billion in Jan 2016 I saw a news reporting here talking about people crossing the borders to purchase tickets and in it the news reporter stated that the customs officer can seize the tickets citing that law.
I think the only way to get around it was if you should have a winning ticket it best to stay there and state your claims ON the ticket THEN after you are awarded the cheque you are then free to do as you please.
May be the rules have been changed since, but since I last checked that's what they were on the books.
I don't think the Canadian government is as restrictive and all they require is if you have 10 grand or more on your person when you are entering the country it has to be declared. If it isn't, then it will be seized if found after being searched. I do know THAT much cause I know of someone who has had that experience. Not a nice feeling.