Given the current backlash against people with blue checkmarks, it'd be very funny if LeBron James or Steven King did sue Elon over an improper endorsement.
LeBron and King have to pick up the negative reactions of their fans over their apparent "subscription" on one hand, and on the other they're fooling other subscribers into subscribing due to the false endorsement.
This is real material impact for both LeBron and King, and for Twitter.
If you let Elon Musk do this now, it sets a very ugly precedent.