system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do contests and giveaways always say "No Purchase Necessary"? Wouldn't it make more sense to rewards customers or incentives more sales?
gpt
It changes the category of the contest so it doesn't count as gambling.

They will often make the 'no purchase' option too troublesome to bother with, such as requiring a self-addressed stamped envelope (so you have to pay the postage for them to end you a contest entry) which just isn't worth the cost of one entry if they come attached to say, a cup of Coke at Mcdonalds.