Everyone is underestimating the effect of culture in this. It's not a coincidence that the only, or one of the only non-Americans in the field was DQ'd. I'm Asian ethnically, Asian-American, I guess, but people, including me, don't like the hyphenation - but needed for this story. Growing up I'd have my two non-English speaking grandmothers visit us in the US. They would do things in public, restaurants for example, that cracked me up. I'd tell them, you can't do that in America. They'd say why not? They just didn't understand, even when you explain it to them. It just doesn't make sense in their world. So they laugh, and keep doing it. It's not as simple as telling them this is the rule. And it's clearly not malicious. Same exact thing with Kilian way back when he was cutting switchbacks at Speedgoat (?).
My take is that Xavier's crew, the girlfriends, likely had absolutely no clue that it was against the rules to provide aid. You say, well the crew should know - it's in the rules. Well how would they know? Xavier would be the one to tell them. But Xavier obviously didn't have a full grasp of the rules, including how serious onlookers might take the rules. That's something an American would not be confused about - they know all about people that are nit picky about things like that, but he isn't exposed to that in Europe. He said that the contrast between the easygoing nature of the race and the harsh DQ perplexed him, and I can totally see that, especially since he came from a different culture.