Like many other things could be strain dependent on how much stress can be taken... but I think this is a terrible practice, that's just my opinion. Though it is backed up by personal experience and research...
Here is a quotable quote for ya " Removing large fan or shade leaves DOES NOT make plants more productive even though this practice supplies more light to small leaves and growing tips. Plants need all their leaves to produce the maximum amound of chlorophyll and food. Removing leaves slows chlorophyll production, stresses the pland, and stunts its growth. Stress is a growth inhibitor. Remove only dead leaves or leaves that are more than 50% damaged."
In my experience it is better to shape and 'mold' your plants e.g. trimming lower shoots that will only produce "popcorn buds"... while still in veg and giving a short while for the plant to recover.
Well, on the topic of fan leaves, spenceje and I are in agreement. I seldom remove fan leaves from my plants.
A pic from day 34 of flowering:
And, a look into the future. After I harvest my current grow, I will be doing an AK47 grow. The AK47 mom plant is ready to give up some cuttings. Here she is:
Everything is moving along fine. It is day 41 of 12/12. It is looking like they will finish right on time, around day 60 or so. I'll start using the microscope in a week or so.
Here is one of the C99, taken away from the HPS:
The buds are a little bigger on the plants under the 600watt HPS compared to the ones under 400watts, but the fans are yellower as a trade off.