There are definitely times that you just can't take an optimal line through a corner. If you are first through the corner you generally get to pick your line and those slightly behind on the inside should compensate for their positioning - BUT - many people don't understand this or feel that they should not have to slow down so I usually leave more space if I think someone might come up on my right. If I were beside someone when starting the corner I would expect to have to take the corner wider. Even when its not a crit we are generally allowed the whole road for corners so its usually not bad if you can get to the front. Be assured that YOU are not doing anything wrong if you are on the front and take the optimal line, but be prudent too because not everyone knows this!

If you are in the pack the best thing to do is to follow the line of the person in front of you. If you find yourself on the inside it is expected that you will compensate and not rejoin the pack at the apex of the turn - which can cause crashes as you cut across the line of the rest of the riders.