"in" or "not in"

[betterin]

Which of the following is acceptable?
1.Join the show.
2.Join in the show.

[Harry Smith]

Which of the following is true?
1.Join the show.
2.Join in the show.

I say: Join the show. when it is clear what we are talking about we can say:Join in.

[betterin]

"join" is followed by an organization, while "join in " is followed by an activity."The show" is an activity held by some TV company, so it is better to say "join in the show".

Is there something wrong with my explanation?

But sometimes I do see "join the show" in newspapers.

Can you give me an detailed example?

[Carolita123]

Hello Betterin, I can notice that you have experience with this topic. Would it be possible if you could help me with the difference between "in" and "on"?
Thank you!

[betterin]

"join" is followed by an organization, while "join in " is followed by an activity."The show" is an activity held by some TV company, so it is better to say "join in the show".

Is there something wrong with my explanation?

But sometimes I do see "join the show" in newspapers.

Can you give me an detailed example?

I know the genral rule of using "join" and "join in", but I want to know why native speakers say "join the show".