Yes, I agree.

As long as there is a space or opportunity to start a tune and things aren't too fast and furious, it's actually a better environment for less experienced players than some more formal arrangements.

For me, being "encouraged" and/or cajoled into playing or singing used to be the most intimidating thing of all. Even now, if I'm not in the mood or the situation isn't quite right I still don't like to feel pressurised.