英语翻译最好口气比较柔和一点的.

这样翻译比较符合国外危险警示牌的惯例：
DO NOT CLIMB （THE FENCE,GATE,ROCKS,etc.）.NEGLECTING THIS DANGER SIGN MAY RESULT IN SERIOUS CONSEQUENCIES.
我在网上随便找了一个国外的危险警示牌,是禁止攀爬木材堆的,供参考：
Do Not Climb the Timber!
Danger sign on timber stacks in Thetford Forest Park.This is a working forest,not just a recreation park.Sometimes surveys have to be delayed until after forestry operations.
“后果自负”可以出现在文书中,牌子上只写可导致严重后果.

请勿擅自攀爬，否则后果自负
No climbing without permission,
Otherwise bear your own consequences
后果自负的地道说法是bear your own consequences

no climbing here, taking full responsibility by yourself

No climbing.Or you will be responsible for what would happen!

no climbing, take full responsibility yourself

请勿擅自攀爬，否则后果自负
No climbing without permission,
Or climbers be responsible for himself.