Frankly, when looking at the reasons that you keep bringing up to explain why your way is better and my way is too dangerous, I'm not actually seeing any evidence to prove that either assertation is true.
A trimmer will wear down the shaft while spinning in a tube, even though the tube is a softer metal. Any body that spins between centers will verify that fact as the soft tube will wear down a hard steel center.
Far as evidence that my method is the best and right way..walk into absolutely any factory on the planet. Show me rows of drill presses drilling away and facing whatever they are drilling. The only drill press you will find will be the one in the shop mechanics room where he drills an occasional hole in something like a bracket to fix one of the factory machines. All the pen parts you purchase are spun with lathes and they are squared with lathes. If a drill press was more accurate, they wouldn't spend all that money on their swiss lathes, they'd just pay some cheap labor to pull the lever on the drill press and be way ahead. If you walked into a professional pen shop, like Mont Blank, you wouldn't find a drill press or barrel trimmer working on their plastics either. They couldn't afford the workers comp. A barrel trimmer was probably invented by some guy with a lathe that wanted to increase his production without introducing a new lathe into his shop so that he didn't have to take the few minutes of flipping a blank and facing it, and if using square pieces, he would have to round them parallel to the tubes first as well, so he came up with this little contraption which does make things much faster and does a good enough job on the average pen or game call, sold the rights or something and got rich...and along the way non-machining type people forgot about the original way which was far more accurate and safe to do.
The drill press is the most accurate tool for drilling a 90 degree hole right?
http://www.efunda.com/processes/machining/turn_elathe_tail_stock.cfm
The tail stock of an engine lathe is used to provide a fixture at the end of the part opposite from the chuck. The tail stock can be used to support a long, thin part so that more radial cutting force can be applied and higher rotational speeds can be attained without a "whipping" instability effect. Below is illustrated another use for the tail stock.
Drill bits can be fixtured in the tail stock to cut axial holes in a turned part. These central holes are more accurate than a drill press or mill could provide since the lathe is dedicated to operations in which an axially-symmetric part is rotated about its central axis. The fixturing is more accurate since all fixturing is based upon surfaces of revolution about the central axis, and the machining is more rigidly supported for the same reason.
Boring
Boring can be accomplished on a mill or even a drill press, but is most accurate on a lathe. The boring tool is fixtured in the tail stock. Again, since all fixturing is relative to the central spindle axis, boring on a lathe is more accurate than most other boring methods, an exception being jig boring on a dedicated jig boring machine. The length of the boring bar is of critical importance because of its tendency to bend. The figure below illustrates a boring tool which is double-ended so that it is less prone to the cantilever "diving board" effect.
You can read tons of articles about how much more accurate a lathe is to a drill online, especially in/from machinist magazines such as popular mechanics or machinist magazine, or American Machinist, or go to CNC zone..the list goes on and on. The lathe is the most accurate drilling machine and the safest way to square something is to face it.
For the life of me, I can't see how. I've always used a vice, v-blocks, and a barrel trimmer on my pen blanks, and never even had a hint of a problem. Had a few blanks get split because of some gnarly grain though...
