Goku cannot guarantee jack shit and he'll say anything to get approval to get the tournament going. Champa didn't even guarantee it. He said he just wanted it for the food and as Super has shown, it took Bulma and Vegeta's schmoozing to Beerus and Whis with Earth's finest Cup Ramen to win them over and not destroy the Earth.
But let's ignore the established relationship with Beerus and look at the other ramifications of a switched Earth.
- Dende and Piccolo lose access to their home, Namek.
- Jaco would probably stay in Universe 7 and his job at the Intergalactic Police, so goodbye that relationship between him and the Brief sisters.
- Say goodbye, King Yemma, Northern Kai and Supreme Kai.
Goku doesn't give a damn about the above though -- especially King Kai. He was asked to not provoke Beerus and he did it anyway. He's so over the fact that King Kai opened him up to new heights of powers. He didn't acknowledge when his gi was transformed to sport Whis' colors and symbol whereas he was grateful to King Kai for leaving Roshi's symbol on his gi all those years ago. He's become so rude with age.