Thanks for all the replies so far. Keep them coming!
For what it's worth, I'm referring to placing chips well in front of the cards, beyond the line if there was one.
I realize that 'the line' can be a whole separate topic, but in this case, it defines the bet area vs the workspace area.
Scenario A, bring out more chips than necessary, and stacking them in the bet area, even if they are in multiple stacks, then bringing the excess chips back, is as far as I can tell, a universally accepted method. Not a string bet.
Based on that, I rule that Scenario B, the 'dribble', even for less than the total number of chips in hand, is acceptable. MikeB points out that the speed of the dribble can be a factor. I agree.
At the time, I ruled that it was acceptable, but that I'd look into it. This thread is the result.
Oddly, during the game and objection, nobody mentioned that the dribble included a count. The blinds were 200/400 and the player had five 1K chips and dribbled them, counting them in the process. When he said "One..." that could be interpreted as a verbal declaration. The bet should have been one chip instead of the 5 he ended up dropping.