> a rational person may understand that 'ideogram' does not constitute an assertion
I'm sorry to see you were downvoted for presenting the other side even if you don't support these schemes.
But I have to ask, what constitutes "an assertion" after all? Written text is just one form of fixing and transmitting ideas; alphabets usually originate in actual ideograms with original meanings that were long lost and were reduced to a sound or syllable.
Transmitting an idea with a text-image combo is just as valid for a contract as any other medium as long as the meaning is clear and unambiguous. And there is no debate here that it's exactly the intention of the organizers to transmit the idea "you can win a car" - and in fact that's what most people understand, with a tiny exception of an educated and naturally suspicious minority. The only debate is if it's legal for the organizers to claim an ideogram that literally reads "Enter to win A CAR" does not imply the car is a prize.
I don't know how a judge would rule, but from a political preference - philosophical point of view I would strongly incline to deny them that right; we get a much nicer society with less scammers, without losing anything of substance.