I can't remember red flags being used until Guy crashed in 2010; ever since then they seem to have become more common place.

I will now sound old, however as per billybookcase, big smashes didn't get red flagged before. The tragic incident with Gus Scott, and the lady marshall, is a case in point; the race carried on, however the accident scene was unlikely to be too clever (I was on the island, but not at the scene, so I'm speculating).

I think the usage of the red flag, and the no racing if it's raining, is due to the new organisation who run the races. That's not a dig at the new guys (they're hardly new, but you know what I mean), as they've dragged the TT into the modern world, and made it stronger than ever. As a result things had to change, and that was a major revamp of safety and organisation - and fair play to them, they've done a brilliant job at overhauling the organisation, whilst making sure the essence of the races remains intact.