A trap in the Slav

This trap is similar to several others where a player plays B-KN5 (i.e. Bg5 or Bg4, depending on color), then follows it up with P-K3 (e3 or e6), allowing the opponent to win the unprotected bishop with Q-R4+ (Qa5+ or Qa4+). These include (a) the notorious 1.d4 Nf6 2.Bg5 c6 3.e3?? Qa5+ 0-1, Z. Đorđević-M. Kovačević, Bela Crkva 1984; (b) 1.Nf3 d5 2.g3 c6 3.Bg2 Bg4 4.c4 e6 5.cxd5 cxd5?? 6.Qa4+ Bachler-Van Meter, Midwest Masters 1985; and (c) 1.g4? d5 2.Bg2 Bxg4 3.c4 c6 4.Qb3 e6 5.cxd5 cxd5?? 6.Qa4+ Van der Heijden-Van Ranwooy, Walwijk 1978. These games offer further evidence for GM John Nunn's "LPDO" (Loose Pieces Drop Off) principle.