Why would you believe them?

Do you believe they have ever seen "things" in space they haven't told us about? Do you believe there may have been "incidents" in space that astronauts have experienced, but told not to talk about? Do you believe astronauts have seen aliens and kept silent?

There are a lot of stories of things that happened in space that have been kept from the public. So why would this ONE bit of information have to be the truth?