Not sure, but some Googling reveals that these three are commonly excluded from contests of all sort. They probably either prohibit all forms of contests and sweepstakes, impose taxes, or regulate them so tightly that it's better to just not bother.

Also note that it may not just be a function of the law, but also of the benefit gained by offering a contest in a given jurisdiction. I'm seeing some indications, for example, that Japan and Brazil have some similar sweepstakes regulations, but it may be more worth the organizers' time to comply with Japanese law than Brazilian. Just a guess.

Some clues:

http://www.slideshare.net/Promosfera/sweepstakes-and-contest... (E.g., server receiving registrations must be located in Italy, steep fines for only brief downtime)

http://en.wikipedia.org/wiki/Sweepstakes ("There are similar laws in Brazil, where sweepstakes must include a "cultural contest", often giveaway questions like 'which brand gives you a house?'")

http://www.theglobeandmail.com/report-on-business/small-busi... (In Quebec "contest runners have to pay tax on the value of the prize. For another thing, contests with prizes over $2,000 have to register their rules with a government agency, the Régie des alcools des courses et des jeux . . . . To top it off, contests with prizes worth more than $5,000 actually have to deposit an amount as a security with the Régie, as a means of protecting consumers should the contest runner fold or renege.")

Quebec has unusual laws with regards to contests (Quebec's legal system is unique in many ways from the rest of Canada's due to its French past)

http://business.financialpost.com/2011/09/08/why-many-contes...

"the province’s Lotteries Act ... require you to post security for contests open to Quebec residents where you do not have a place of business in Quebec, the value of any single prize exceeds $5,000 or the total prize value exceeds $20,000."