At the beginning of Star Wars: A New Hope, we see the Rebel Blockade Runner with Princess Leia and the Droids being pursued by a Star Destroyer above the planet Tatooine. Practically directly above it, close enough that it could almost be in orbit.
It seems an incredibly strange coincidence that they should run so close to a planet that just happens to play host to Darth Vader's estranged son and former mentor before his turn to the Dark Side. Moreso that they'd fly so close to any planet at all, when space is so vast and empty.
What reason did the Rebel Blockade Runner have for being so close to Tatooine during this chase?