Staying on topic,  to answer your question,  it may lay in the fact that tight fitting clothes are easier to model and poserize due to the spherical fall off zones of the original figure.

Now on to the OT.  I'm still waiting on Stacy 73's and Maveris's permission.  So we'll start with the help I received from WillDupre over at DAZ.  I quote.

the inner falloff sphere for bend is very tight in the Y direction particularly on the underarm a few inches from the elbow, and the outer falloff sphere barely meets the inner at that position, any thickness at all in clothing will cause that spot to fall outside the two spheres. scaling up the Y on the inner falloff sphere slightly should fix your problem.

Here is a tip to see what is going on more clearly with falloff spheres. with the sphere selected go into Display>Element style and change the style to wireframe then do the same with the other sphere, this will turn your spheres into wireframes which will be a lot easier to see and see where they overlap on the clothing. unfortunately P6 has flakier joint editing tools than P5 (contrary to popular opinion I use P5 over P6 for this reason primarily) so you wont see the falloff spheres in color like you would in P5 which makes it a little harder to judge where they cross, also P6 has a maddening habit of making the centerpoint on the screen jump around as you change camera positons.  http://forum.daz3d.com/viewtopic.php?p=784909   end quote.

If anyone would like I could post diagrams.