I find that keeping plants in party cups too long, can increases the time it takes to determine sex. I mean to me, the faster and bigger you can get your plants, the faster they show sex. It's stunts them to keep them root bound but at the same time a lot of us don't have room for bigger containers while waiting to cull. Without stress, you can't see how reliable they are. If you are simply looking for sex, I wouldn't stress them.
I also have the opposite theory when it comes to male/female. I think stressing them can be good and here's why. I believe they will show their true sex that way. Why find out later a particular female has male traits, hermie? If she is going to show it, she will show it from stress. There is also another problem, the late flowering hermies at the end of harvest. The Chemdawg D cut loves to throw a few nanners here and there at the end of the cycle. I think it's better to have less females than a bunch of females that are prone to changing into dudes.
That is just my take on the subject.