The way to know which principle you should follow is to ask yourself: am I in the position to set a de facto standard? If you are, then be conservative in what

The way to know which principle you should follow is to ask yourself: am I in the position to set a de facto standard? If you are, then be conservative in what you accept, and prevent whole categories of problems in the future. If you're not, then it's too late for that. The damage is already done. Be liberal in what you accept, and try to mitigate the resulting harm.