As the sidebar says, it's recommended to include your model but not a rule. I like to think this is first and foremost a community to share the images you've generated. I'd hate to scare off potential posters by putting up strict requirements.
That said, of course I wholeheartedly endorse the sharing of models and prompts. For my own posts I like to put the model in the title and include the prompt in the body. It's easy to do for Midjourney because the prompts are usually quite small, but I can imagine it can become quite a chore for some of the more complex workflows.
Though I tend to skip prompts and models when it's just a one-off comment in someone else's post.
On a side-note, this my 1000th comment! 🎉
Midjourney prompt
a tall fancy cake with "Thelsim 1000" spelled out in burning candles --v 6.0