In the 2009 match between Judit Polgar and Evgeniy Najer in Richard Riordan GM Blitz the following strange(?) opening sequence of the Najdorf was played
[White "Judit Polgar"]
[Black "Evgeniy Najer"]
[Result "1-0"]
[fen ""]
1. e4 c5 2. Nf3 d6 3. d3 Nf6 4. d4 cxd4 5. Nc3 a6 6. Nxd4 e5 7. Be3 Be7 8. Nb3
Black refuses to take the white knight on both move 5 and 7 but why? I see no horrible threat if the capture is made.