Amazon blocks non-Prime members from purchasing certain games

Amazon has extended its “Prime-exclusive items” to video games, preventing non-prime users from buying select titles.
Amazon users began noticing the update in the early hours this morning (via VideoGamer). Among the games now listed in Prime-exclusivity are the PS4 versions of Rainbow Six Siege, Assassin’s Creed Syndicate and Battlefield Hardline. Halo 5: Guardians is also exclusive to Prime members on Xbox One.
Non-Prime members, instead of seeing an “add to basket” option, will notice a blue box identifying the product as “Prime exclusive”. You can still purchase the product from third party sellers, but not directly from Amazon.
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At this moment in time, these are the only games currently spotted as being brought under the Prime-exclusive umbrella, whether or not more are added remains to be seen.
Amazon Prime costs £79.99 annually, and includes access to Amazon Video, unlimited one-day delivery on select items and also Amazon’s new music service. Members also get access to over 50,000 eBooks for Kindle devices and apps.