It's all about verisimilitude, friends, and TOS had it in spades.
So, in no particular order...
1. No use of communicators during normal shipboard situations. Use the intercom.
2. No sidearms carried or within reach during normal shipboard situations.
Next?
So, in no particular order...
1. No use of communicators during normal shipboard situations. Use the intercom.
2. No sidearms carried or within reach during normal shipboard situations.
Next?

But we can infer that the approach plane may have been just a courtesy and not something which was always used.
)
. This has got to be the first time I've ever heard the concept of "realism" used in conjunction with the TOS uniforms. 