That sounds like a lot of fun. Did you get to pick the teams or were they chosen for you? I used to hitch hike in college from time to time. I stopped after being picked up by two weirdos in a van with beer cans all over the floor and hand guns visible. They never said a word to me. It was terrifying. All my other experiences were fine. Your next adventure sounds amazing too. Good luck!
We got to choose the teams, but I met my partner only 2 weeks before the race. We were discussing travelling destinations with friends and this race came up. We had a mutual friend which organized the race and we called him up and it turned out a team just signed out of the race so there was a new spot. We got pretty lucky there. There was 3 'accidents' : a team got in a truck and arrived in a hangar to reload the truck. Nothing happend, but you never know and it might have been dangerous. Another team got picked up by a huge weed-smocker. The guy had a carboy oxygen that he used after smocking to breathe while driving, pretty surreal, but they arrived safely. Another team got to an after party at 7-8 am in Hambourg and the host had a shoebox full of weed, was doing rails of coke and showed off his gun. At the end, everything went fine and it was fun, but it's risky.
I don't know if i'm going to hitchhike again. You can meet a lot of people and that's fun, but I find the argument 'it cost less money' lacking in the sense that, to get to Copenhagen (1400 kms), we did it in 40 hours while the best team did it in 30 hours. We can work for half of that time and take a car-sharing services to get there. It's less adventurous, but it's more secure. It's difficult to find a great balance.