Courts generally know that people don't read fine print, much less understand it. So if there is something courts see as a promise that people will see and understand they will tend to decide that when the fine print is in conflict with advertising they tend to assume that there is an intention to deceive and so they will punish you for it.

When reading the above, think: the opposition lawyers have incentive to present the case that way. Judges rarely stop them. Juries tend to accept the above presentation. Of course the other side has lawyers that will try to pick apart that argument. It is anyone's guess what the jury (and thus court) will decide.

There are many different legal systems in the world. The above is a US perspective. I cannot comment on other countries, just know that each is different. Even if Tesla wins in court in the US, they can still lose a lot of money in other countries that work different.

Since Tesla thinks they are clever by not running "ads", but instead relies on their own "viral marketing", they may find it rather upsetting when they go through discovery and there are heaps of internal memos talking about how it is important to market the idea that they are selling FSD forward, very directly misleading customers.

Just Elon's public statements should be upsetting.