what the meaning of this link in linux script

Question

What is the meaning of the following which is on the top of linux script

#!/bin/bash
return &> /dev/null

Answer 1

The line is to protect users from sourcing the script.

When the script is run (not sourced but run), the script will proceed to the next lines until the end of file.

When the script is sourced, the script will just return and do nothing.

Answer 2

return is supposed to return value from bash function.

When used exactly like in your example but without &> /dev/null, it is invalid use because return does not belong to body of bash function, and would print:

line 2: return: can only `return' from a function or sourced script

However, somebody decided to hide that error message by piping output to /dev/null.

In other words, this all does not make much sense.