In fact, they gave an opportunity for future time travelers to contact them, requesting that the contact be made before the offer was extended. Since they obvi

In fact, they gave an opportunity for future time travelers to contact them, requesting that the contact be made before the offer was extended. Since they obviously knew at the time that that hadn't happened, the only value was in proving that if time travelers do indeed exist, they don't wish to make themselves known. (A fact that may seem obvious, but I could see a legitimate time traveler having a difficult time proving their existence, given that people will ignore significant evidence in the face of the impossible.) So in that case they actually know the result will be negative, but there's still some value in doing it.