I have done more solo backpacking in the last few years since some of my regular hiking partners have become less active. But I never kid myself - solo hiking is not as safe as with a group of experienced backpackers. I am willing to take that risk rather than stay at home. But what I really should do is spend more effort finding new backpack partners. There are a lot of advantages of solo, but safety is not one. As for the "hazard" of a newbie with you - add another experienced person. By the way - I do not consider solo hiking a popular trail such as the JMT a "solo" venture - it is more like being part of a huge unorganized group.