I believe this technique would work, it's just a matter of how practical it is. If you have your opponent in a side position, controlling the arm, it'd probably make more sense to go for an omoplata... but if your opponent tries to turn in to you, stand up and possibly stack you... you could go for the triangle and break his balance and posture. Personally, if the guy is just sitting there not moving, I'm going for the omoplata.