I've had recent experience of this. I'm normally averse to things tight, but the lure of passages new overcomes it, usually.....
I pushed a squeeze in Waterways, now called the "Tourist Trap". It was a nice smooth bit of flowstone floored tube, but at a certain point, your ribcage pops down over the lip of a gour dam, and you are "commited". The way on was reasonable size, and fortunatly I could get out from the far side by an abseil with a rope tied to some nice calcited rubble
Return through the squeeze was impossible for me....
Far worse are the stories of blind free dives, eg Swildons 1, but then they were 'ard in them days.... or the exploration of the Milwr tunnel. Several miles solo on an inflattable li-lo in fast flowing water to a possible exit...or possible blockage....or possible bad-air