They had 40 cars on a smaller track previously with no complaints. If the drivers thought their was too much risk they'd refuse to drive, as has happened in the past, these guys aren't shy
A much safer model is being introduced for next season, although you have to realise that Dan's car was inflight, smashed his head into the safety rails, and then burst into flames at 200mph, the drivers area was pretty much undamaged, it was the head injury and that likely killed him.
We've had airborne cars in F1 this year, luckily they were on straight parts of the track. Luckily the last death was Senna, but people forget that the same weekend Roland Ratzenberger also died in practise. Senna was also a head injury from flying debri penetrating his helmet, something that nearly happened to Barrichello (was it him?) a couple of years ago, but luckily just knocked him out.