in racing no doubt I believe you should have the safety I just mean in street accidents I feel like it would have to be a pretty big accident to submarine lol.
no nothing holds you into a kart, they require slightly larger balls to hold you in. but im not honestly sure you should be strapped into a kart.. seems better to be ejected than ride that rollercoaster

The first time I got into a race car I felt invicible
there was a lady at grand nationals racing with us who hit a guy in a flat out chicane at eagles canyon. (the guy spun and she collected) she essentially submarined into the kart. luckily she recovered but they had to air lift her out with multiple compound fractures. I had the pleasure of getting ejected once into a light pole when mike jones tire blew out next to me on the straight in denton. Cracked my helmet visor and broke the carbon on my helmet lol. shits not safe at all

this seems to happen too
http://www.youtube.com/watch?v=cs6aU9qUtNQ
http://www.youtube.com/watch?v=zD183...eature=related
2:30
http://www.youtube.com/watch?v=ZSgNM...eature=related