If that did start happening, it's not like the people from the past would just pop up suddenly. We would be aware of their journey. It's not like a time machine where someone just disappears from the past and appears in the future.
Sure, and we would probably be able to tell when they were from based on the approaching crafts. It’s going to be amazing to be able to step 50,000 years into the future to see how humanity has turned out. I’d give up anything to have a chance at that.
You could always take a flier on cryonics.
If you stop to think, a trip to the future is a trip to immortality because you can go to a time where the technology to live forever will be available.
Unfortunately humanity is constantly on the verge of self destruction so I would expect to come back to a radioactive smoldering place with some survivors roaming around still trying to finish one another with sticks and stones.
After the first time it happens people in the future can start to expect a human from the past to keep visiting every so often.