It never happens.
It not being as frequent that I find someone that reads it would be the same thing as never happening, because I skim through just about everything that pops up on the forum. So yeah. Very infrequently do you see someone on their first post do everything the right way.
@amhndu Why would you consider not reading the sticky a mistake? Someone could very well make a post properly on their own(not saying it's good to not read the sticky, just saying it's possible for someone to actually make a well done post and answer back properly).