While I'm a bit "disconnected from a current'racer'", I will say that "leeching" has been around for a while.

I will also state, while you can leech, it does NOT mean you can climb as well as another when you're "scrapping the trees".

I've, "been there, done that" and lost a good regional placing trying to go for a slightly higher podium position.....

"Way back when......", I remember pilots picking starting positions in the morning. When a "hot pilot" picked a start time, a "whole gaggle picked whatever time was shortly thereafter......".
This was back when I was a crew..... likely before some in this thread were born......

I still say, "You can follow a better pilot, but can you "really" core a thermal & get away??

Best I can come up with is...... I did a "pass" in a thermal (of a slow climber) and looked over my shoulder to see KS & SM following me.
Likely will never forget that.
No, they kicked my butt...... sigh.