A conspiracy so vast, it would have had to include the victims themselves as participants.
Had Diana, Dodi, et al been wearing seat belts, they would have all survived the crash.
Had Diana not hated the British Royal Family so, she would have been under the Police protection of Scotland Yard. She refused, and trusted herself to the private security of Mohammed Al Fayed.
Conspiracy? Don’t think so.
Stupidity? Definitely.
The " .. al" here was Henri Paul, the (drunk) driver. The one person in the car who was sober and wearing a seat belt - the British government bodyguard - is still alive.
I just can't be all that sorry for people who were stuck on stupid.