Two things strike me here:
1) you assessed that they was a risk and thought through it, you were not over-confident - this is good;
2) your group knew this but were in agreement to continue.
I think there is a lot to be said about a group leader making a sober assessment about his/her own abilities and experience, the strength/fitness and moral of the group, as well the weather and overall situation.
As a leader, if I am confident of my ability to lead and genuinely have the welfare of the group in mind, and if I have explained any risks or unknown factors to the group, and together we have reached a decision that all are confident with - then I can face many adverse conditions. Even if something like getting lost or an injury should occur, this is something that the group will be a lot more tolerant of and the reaction will be a better one.
Granted, hiking in the mist does have its risks. But it is not necessarily something which should cause a hike to be called off. There will always be risks, even if the conditions are good. What counts is your attitude, sober judgement, cooperation and a team spirit.