if the winds blowing from the right direction and the beach is clear and it's a good set up then i'm out there no worries, the less people around the better i reckon

A lot of kitesurfers won't go solo cause they need their kite betty.

Back in da day, when I was teaching in Sydney, I would regularly ride solo as I had the time during the day whilst everyone else was at work. Also in big winds I tended to ride solo (+30 knots) as there were only a few of us game to go out when it got a little over the top, especially at Cronulla when it was BIG in a screaming S'Westerly.

I reckon solo kiting rules if your competent in your ability to handle it. It's always best on your own IMHO. If you have rarely kited alone and aren't sure of your ability to get yourself out of trouble if the need arises, then dont do it. Never underestimate the conditions or overestimate your ability and you will always be fine.

But only if you are totally confident with all of the above.

40% of my kiting is done solo and its great when everyone else is working. That is one of the few benifits of being a shift worker.
Trust your gear and know your limits and rip into it.Some of my best moves are done solo so they are hard to claim.

90% of kiting I do alone. I live at the south end of a long beach, and at the Far Northern end is where everyone else goes. It's about 7k's away.
I kite at this spot because I live there. Convenience is a big factor if you're busy and need to fit kiting in around other things.
It's at the mouth of a crocodile infested river, various sandbanks. Submerged tree roots and wood pieces that disappear underwater at high tide. Pretty close to the airport, old dilly pots, Stonefish, and of course the cyronex fleckeri (Box jellyfish) from November to May.
Despite this I kite at this spot because A: I live there, I can get out on the water within 10 mins of the weather being right. B: Its amazing because of all the sandbanks, mudslides (100m along a mud channel with no water on a skimmy - great fun) and constantly changing conditions as the tides move in and out.

After a lot of consideration (and pressure from my wife) this is what I do to try and make it safer.

Like any maritime activity, I think you can kite relatively safely alone provided you:
A: are a competant kiteboarder (staying upwind, know how to tune the kite, know how to jump safely), and know a lot about the local weather.
Tell someone that you're going.
Make sure the weather has no surprises - BOM Radar, any cells nearby that need to be taken into account?
If you're alone, only kite where you've kited before. New launches, alone - it's just stacking the deck against you. If there's someone with you (non kiter) then it's a different story.
Don't try your hardest core, most progressive tricks. Turn the tempo down a little and try to kite with style and smoothness - work on all the aspects of your kiting that don't elevate the risk of injury.
Don't be in a hurry to set up.
Wear the appropriate safety equipment.
Know where the nearest phone is, or how you would make a call. Look out for other people at the area (non kiters), and if you want to be really careful, tell them what you are doing and that if they spot you in trouble, (single arm waving overhead) then could they notify someone.
There are waterproof cases for mobiles too and that could be a lifesaver.
I think the most important thing you need to consider is how far way help would be if the worst happened, and if that's longer than acceptable, common sense should kick in and you should do something else.