Just another thought on jam sessions; something I've always been aware of. Without a good drummer (especially the drummer) and bass player, no matter who else shows up the jam will be a disaster. So, in terms of the drummer and to some extent the bass player, I say something similar to Grumps. If they can't play well, they don't belong there. I feel bad saying that because beginning drummers and bass players deserve to have an opportunity to learn to play with others, but it would be best if they did that with a private rehearsal band. The issue is, without a solid drummer/bass duo, no one else on the bandstand will have much chance of sounding good.
Is that too "hard line"? I'm not trying to start trouble, just stating my opinion. Please feel free to disagree; I won't mind.
Still gonna disagree, although you make a valid point. Jams are not hazing mechanisms.
To your example - I think that yeah, it only takes a woefully unprepared musician ONE jam event to learn the lesson 'yipes, I was woefully unprepared'....hopefully...
let's say ...70% of the time.
The other 30%, people still miss entirely how 'bad' they actually did.
Interestingly, this DOES happen with drummers quite a bit. They show up, think they can 'jazz'...and from bar 1 the train is off the rails.
But the comment that I still remain critical of, despite the commenter's repeated attempt to recharacterize it...was that if one needs sheet music, they aren't ready to be public (jazz) jamming.
That is just completely passe...superceded... by the realities of contemporary jam sessions.
Example - Trumpet Mafia, New Orleans. A jam that has been going on for, gosh, two decades or more, different venues over time. Mostly a set rhythm section of regular players and then hotshot, mostly young trumpeters primarily (although by the 'rules' a trombonist or reeds player COULD attend, but for most part do not) flood the jams and try to outdo each other with their bravado. It has become a New Orleans attraction in and of itself, it historically has drawn patrons over the years..
I know of this because our trumpet player moved there and dove right into it, quite bravely.
Those hotshots....have their iPads or phones on hand. Most of them. Quite advanced players with good chops, massive egos, and testosterone overflowing...they bring music. Because they wanna play on tunes they might not know, rather than sit out...
The notion that this is inappropriate, or that they are not 'ready' to be attending one of the penultimate shred sessions in the US...is not supported by reality. One can wonder 'with all the apparent work they HAVE put into becoming that level of player, why DON'T they have the 300 most common tunes memorized ?"....but there really are several obvious answers to this, eh ?
Likewise the notion that a developing player should not attend or sit out tunes like Watermelon Man, Song For My Father, etc...because they rely on a chart to get thru it.....makes no sense. If they have a rudimentary grasp of the changes they see in front of them...they have every reason to be there. If they flub the tune because they had no place to mount their pad and refer to the chart...the next time, just bring the stand...rather than necessarily memorizing the chart.
In an instance where this was the first session attended by a player, and said player HAS been developing pretty well (compare Alon's recordings in '26 with ones from two years ago - night and day) and has begun to grasp and employ some fundamental improv theory...and has developed a respectable tone and has decent mechanical fundamentals .....
...the checklist item of "Do I have any/many songs memorized ?"....is completely moot, IMHO. It carries little weight in swaying the question of 'should I dive in there or no ?"