I don't get the inner tubes thing, they're a fiver FFS
This has happened to me twice, funnily enough at trail centers:
The first time was at the Marin, just as we were flying down the last switch-backy-bit before the car park there were 3 people stood on the inside of one of the corners fixing a puncture, thankfully I managed to stop in time otherwise it may well have been a bit nasty.
Second time was at 'degla, a lady and a couple of kids on the blue finish under the bridge, thought the middle of the berm was a great place to stop and wait for hubby/daddy. Just as well there's plenty of space there
On a riding over people note, my mate did come off in front of me on one of the descents on the Pont Scethin route, we were descending along a bit of single track that was like a mini rut, about 12" wide and a few inches deep - not enough time to hop out of the rut and faced with a decision of squishy human or Orange 5, I chose the latter and rode straight over his back wheel/swing arm.
All of us escaped unscathed, I only had to justify that the bike was inevitably less likely to be damaged than him considering his glass back :lol: