I have thoughts.

It was ridiculous that Hawking thought a time traveler would make it to his party for several reasons. There are a few models of time travel, and only one of them has an internal logic that allows for traveling without paradoxical consequences; multiversal divergence.

Our version of the time traveler party was one of an infinite amount of time traveler parties that hawking hosted throughout the multiverse. A time traveler would be traveling to that time like picking a grain of sand on a beach, where each grain of sand is a near identical party to the last.

As our version of the party diverges from the realities with time travelers who chose to travel to the hawking party, there would be a diminishing set of infinities containing time travelers that were attempting the journey.

Thus while the chances of a time traveler going to the party are 100%, the party being our version of the party approach 0 infinitely fast.