Do they always have to be organized at a big place, like bar or club or are there any more low key ones like at an actual home?

As long as you are careful and discreet, the worse part will be the stains on your carpet.

Luckily I have wooden floors. You stain it you clean it sirs and ladies.

meatball sauce, red wine, and mustard, that kind of thing.

Now we know who has a naughty mind.   8o)

There have been many different kinds of M&G's in NYC.  Some big 150+ person events, some small 20-30 person cocktail party type events, and some small dinner parties with a dozen or so.

Re sex at M&Gs, while it's not the norm it does happen.  I've been to one in NJ where the Champagne Room of a cheesy strip club was used for sex.  A recent one you may have attended included sex in one of the bathrooms that the male told me he paid for.  And there's sometimes even OTC sex.  Someone we both know and I were talking to an older provider when she suddenly asked to give him a free BJ in the bathroom.  At another party the guest of honor tried to convince me to stay by pulling my cock out and sucking on it while a handful of people watched.  She said too much alcohol makes her do things like that.  One more reason I like her.
Point being, the rules vary and are inconsistently enforced.  But I agree it's important the guests know what the rules are.  Then it's up to the host.
That said, I agree with everything else, especially the part about verification.  Guests must be verified as stringently as a smart provider screens her clients.

I would argue that any party where there is a "champagne room" is not a M&G, but a play party.  If it was advertised as a M&G, then I think that was incorrect.  The purpose of a M&G is simple to make connections.  

The type I'm thinking of would definitely be more of a dinner party in a chill downtown home, to actually meet, greet and converse over cocktails and wine.

It was my first M&G (in NNJ), run by the same guy who pulled the stunt in NY with the reporter.  So it was a clone (pun intended!) between a M&G and a play party.  Screening was the same.  As for the purpose of M&G's, I agree, and, yes, people will misbehave, especially when the purpose of the gathering is all about sex to begin with and there's lots of flirting and ass-grabbing.  Certainly, it's important that people know what kind of party they're going to.  And when a gathering goes from innocent (or even not so innocent) play to play-4-pay, that's were the danger lies.

I've attended numerous of these events in NYC, and each experience is unique.  They can be organized anywhere...bars, clubs, hotel suites, apartments, houses.  Attendance depends on what the host or hostess plans for, for the most part.

I have been to many large and small it really depends on the host on how the party turns out

xoxoxoox