Exercise 2: Two Sessions With the Same Name — Possible Solution
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Commands:

  screen -S test     # Ctrl-a d
  screen -S test     # Ctrl-a d
  screen -r test

Result: screen doesn't pick one. It lists both matching sessions, for
example 31100.test and 31112.test, and asks you to type a more precise
session identifier.

Two ways to reattach one specific session:

  screen -r 31100          # the PID alone
  screen -r 31100.test     # the full PID.name ID

Either identifies exactly one session, because PIDs are unique while
names are not.

WHY THIS WORKS AS AN ANSWER
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It shows that names are convenient labels, not identifiers, and that
the PID part of the ID is what guarantees you reach the right session.