This seems highly company specific.

Are you asking for what the Analysis Paralysis Expert should do if he attends your meeting? Or how you can mitigate his effect if he attends the meeting?

We don't know him, so we can't tell you how he's likely to behave (probably about the same as if he were just regular-invited - being forwarded in honestly doesn't change much). You may have a better question if you focus on how to uninvite him, or how to respond to his behaviour that would usually ruin the meeting (with details about what he actually does), or something along those lines.

I am asking if there is a business etiquette for showing up to a meeting where the organizer did not invite you. (I could edit the question if I failed to ask clearly enough).

Meetings get forwarded to other individuals all the time in my experience. Agree with @Erik in that your statement is highly company specific.

@Erik I agree, but we are a big multinational so the highest of standards are expected from us.

Is he really looking that forward to this meeting? Can't you just de-invite him?

The issue can be solved with a talk and an de-invite, but my question is more related to what is the professional approach from him, if he wanted to attend.

FYI there is code for exchange you can try that prevents meeting invites from being forwarded, if your email system is MS Exchange.

Thank you all for trying to find solutions. I do know I can set up meetings which cannot be forwarded. It would be nice if I got answers for the actual question.

"The business etiquette is rather clear on the fact that it’s a no-no to forward meeting requests without consulting with the organizer" - do you mean your company etiquette or business etiquette in general? Because adding useful or necessary attendees (without consulting the organiser) is common in my experience, and if it's specific to your company, the answer to whether it's acceptable to attend such meetings would probably also be specific to your company.

The answer to the actual question is "he would attend the meeting if he wants to", unless there's some company-specific policy that tells him otherwise.

As stated originally, it was not useful to invite that person (tech presentation, non-technical person). I am interested in regard with general business etiquette.

I think the answer here is there is no general business etiquette to guide you in this case. You have to look at the culture of the company, and work from there.

i've worked in large multinationals with the utmost respect for professionalism. meeting invites still get forwarded.

I understand what you are saying. This happens everywhere in day to day work.

You're asking for what is the professional behavior from him, but you can't control or change his behavior. It doesn't matter what is appropriate - he will do what he does. You can ask how to respond, how to uninvite him, how to talk to the person who forwarded the message - all sorts of things that you could do. But you have no control over his actions, so what is the benefit of asking what he should do?

@thursdaysgeek The benefit is the following: I don't want to have a misperception on his actions if he either did not do anything wrong by participating, or did enough (should he approach me or something). I do not want to jump to conclusions about this colleague's professionalism, until I know how he should have handled this. I do not want to pass judgement because my common sense tells me that it is not ok to just attend in the meeting, but I might be wrong.

"...big multinational so the highest of standards are expected from us". I don't see this connection. I've worked with/for big multi-nationals where they had horrible business etiquette.

@cdkMoose since you known there can be horrible business etiquette, it is important to know how they should be (opposite of horrible). Hence my question. I understand that in practice such rules sometimes don't apply, but it is still important to know what is right/wrong and why.

@FremenLord, When I said horrible, that was my opinion of their etiquette. Business etiquette is very much driven by the corporate culture. I've seen cultures where cursing was perfectly acceptable and others where it would get you fired. There is no one answer to this question, except to look at your company's culture. And even that can vary. The culture in an office in Tokyo might be very different from one in the US, even for the same company.

I don't understand this. My question is broad enough to be general (how should someone do something in some kind of situation, so that it is professionally acceptable). I summarise all of the answers in : it depends on culture and block meeting forward. I understand both, but I was expecting more than this.