I just thought of writing this as it happened to a teammate recently and it's actually annoying if/when it happens to any of us. I understand that everyone has to be careful but spawn peek really kills the enjoyment of the game. Everyone can spawn peek if they want to but where is the enjoyment in that?
You know that red barrier that appears during the preparation phase? Maybe not everyone will agree with me but I do believe the only way to get rid of this problem once and for all is to maintain the surrounding barrier for around 7 seconds after the preparation phase, let it block every bullet heading out. After that 7 seconds, let the defenders do as they please. I am as confident no one will be complaining again.
I don't actually want this but I think it's needed as a lot of defenders keep spawn peeking. It's an enjoyment killer. I don't know why people are so thirsty to get an early kill.
Do tell your thoughts or suggestions.
EDIT: Title was supposed to be be Spawn Peek Solution / Suggestion... lol.
Fixed the title for you!
Spawnpeeking is an ongoing topic the team has been monitoring. I know the team has made some slight adjustments to maps to help correct spawnpeek locations the team deemed as unbalanced. I think having an understanding of where the common spawnpeeks are is necessary to play at a high skill level, since they may be used more often. Most maps have several ways to counter these spawnpeeks, like choosing a different place to spawn.
As bee mentioned, some spawnpeeks don't require you to actually do a runout to do it. While your suggestion helps mitigate a few on certain maps, it isn't a complete answer to help resolve all of the angles.