I'd say that the player who has to fudge the beat to accommodate ornamentation would do well to schedule a private meeting with a slow metronome, upping the B.P.M. incrementally and perfecting at each speed before moving up. And I'd say this is best done before any more playing with others. Or back off the ornaments and allow the beat to roll out evenly. With few exceptions I feel beat-stretching to favour an ornament is anything from thoughtless on down.

Every teacher, guide and coach I've had in my music journey has taught me to keep the rhythm no matter what else fumbles, and get the "what else" back on track as soon as one is able. If not able to do that, it's too fast--therefore simply drop out, or, if circumstances permit, start again more slowly.

Of course because this is how I was taught it's what I think is the right way to deal with it. It seems to me a more gracious approach than messing up the whole.