Rick,
I agree cookies would be a more secure marker, particularly in the case of flow. I believe this is the main reason they are used in favour over pegs, and in the US where flow is quite extreme, I would use them too.
Talking to Dave Raymond the other night about his US dive trip to Florida and Mexico, there are places where you cannot swim against the flow, you HAVE to pull yourself along the bottom. He came across a diver on a Gavin who had to kick like hell to make headway with the scooter going flat out.
I can see the benefit in them, just not here. They are slower than pegs to attach, and harder to retrieve. I honestly believe if the US guys were from here, they would not see the added benefit of using cookies. I have NEVER had a peg remove itself from the line. The arguement that it can be kicked off is bollocks, and if your buddy cant avoid the line, maybe your training is not as good as you think......

Interesting you chose to use pegs on the pen course, but not after. Why?
Seriously, have a look around at the guys who have been diving here for 30 years. These guys are no mugs.
JD