What do you mean?
If both players have not played a stone, no-one can win the game: if it does not proceed it is cancelled and annulled.
The essential question here seems to be one of “etiquette” or “what is socially acceptable” (not related to winning/losing tactics).
As a one-off, almost anything is acceptable. Broadly, it is acceptable to cancel a game before it starts. This capability is there to cater for people taking too long to join the game, maybe accidentally not noticing it started, and avoiding forced waits under those circumstances.
It is also there to allow people a chance to double check who they are playing and the conditions of the game before committing to it.
If your partner calls for dinner right at the moment that you accepted a game, it is OK to cancel immediately it the game starts. A chat comment apologizing will help in this case.
If you got distracted and didn’t play your first move for 5 minutes, this is also OK because you know your opponent can cancel.
What is not OK is repeated “abuse” of this flexibility. This is a grey area, but people who continually cancel games, or continually make their opponent wait excessively to start, are asked if they can please fix that.