I've been crossfitting and eating paleo for about 3 years now. Its actually inspired me to start my master's degree in nutrition!
I im in Ketosis most of the time, and also have very low blood sugars.. I rarely spike above 150, even after eating. Take a look at my blood sugar reading on my CGM for a 24 hour period--- http://www.1happydiabetic.com/apps/blog/show/10333424-my-blood-sugar-for-24-hours
Pretty cool, yeah?
As far as I can see it, ketosis with well controlled blood sugar is perfectly safe. Ketosis with high blood sugar is dangerous! I think its very easy to stay away from high BG, especially if you are eating right, and regularly checking your blood sugar (or have a CGM like me).
Many believe that ketosis is actually the optimal human condition. The brain thrives off of ketones. I definitely am way more sharp when I am studying in ketosis then when I have had some carbs. (just remember, that it does take some time to get fat-adapted, and during that adaptation time you can feel sluggish and slow)
Also, I have insane energy for crossfit while burning ketones. If you know the WOD's, I did "Cindy" last month for 26 rounds!
Dont be scared of ketosis! be safe, try it out and see if it helps you.