I got called for a string bet once in a 1/2 B&M game when i tried to raise to 4 on the turn. I had 4 chips in one hand, reached out, way in front of me and dropped two, then another two right after each other. I mean, drop-drop. Almost simultaneously.
What I had been upset about was I had just played a NLHE tourney before that and a guy reached forward with a stack, and tried to drop just half of it. They made him leave the whole stack in the pot because he had put them acrosse the imaginary bet line.
I would've been satisfied with consistency.