Yes, the US Supreme Court ruled it unenforceable in 2013: https://en.wikipedia.org/wiki/Kirtsaeng_v._John_Wiley_%26_Sons,_Inc https://en.wikipedia.org/wiki/Kir

Yes, the US Supreme Court ruled it unenforceable in 2013: https://en.wikipedia.org/wiki/Kirtsaeng_v._John_Wiley_%26_Sons,_Inc https://en.wikipedia.org/wiki/Kirtsaeng_v._John_Wiley_%26_So.... But it was easy to find resellers ignoring those restrictions before. I got some expensive scientific books that way in 2004.