Sadly, even that doesn't work. One race I was so fed up by this one guy (sporting a Borat livery) I went out of my way to make sure he finished last. I had already raced him a couple times, he's not fast but simply barges and blocks his way to the front knowing how to avoid and deliver penalties. This time he again deliberately ran into me. while making a clean pass, to deliver me a penalty.
So I started slowing down, keeping my car right in front of him, letting the other drivers through (We were at around 5th at the time). If he managed to somehow get aside I pushed him into the wall. When he spun I stopped to wait to resume blocking his ass. I got about 12 sec in penalties in lap 1 but he was dumb enough to hold back about a minute before the straight hoping I would leave him alone. I did, I sped on to the straight, serving the penalty and only fell 5 sec behind when he passed.
It didn't take long to catch back up with him, rammed him off first, then block again letting the rest of the field through. He was not a quitter, kept trying but could not get passed me. And when he did, due to ghosting, it didn't take long to catch him again a corner or two later. I had about 16 sec penalties that round but finished ahead of him since we timed out before the straight. After the race I type, "Are you going to behave now". Lot of cursing as response of course. I went off to better races in SR.E, good riddance.
Did it work, nope. He's actually on that video I posted in the penalty thread. I pass him at the 5 minute mark, then he tries to pay me back at the end of the middle straight but fails spectacularly. That still didn't do anything, next race he gets called out again by multiple people in the room.
I've tried it on other people as well, 2 in one race, kept them both behind while serving penalties in between. I got them down to the back of the field while still finishing ahead. One thing you learn in this game is how to drive dirty, plenty examples everywhere

I told them why, but just got 'grow up' among the more colorful responses.
This game has changed so much. The "Thanks for the clean race" option might as well be removed as well as "I'm sorry". Out of my ~80 races getting rammed, side swiped, dive bombed, punted, I got one "I'm Sorry" from a Brazilian and I didn't even know what he was sorry for. Whatever he did wasn't on my radar as anything dirty. It must be when he messed up and I slowed down not to hit him, thus got bumped by a car coming from further back. Not his fault, yellow flag doesn't mean speed up.