I had the same issue when trying to find a first knife for my son(6). Lockbacks seem like a great idea, except that they all require putting a digit in the way of the closing blade.

I settled on a Case Peanut with a bone stag handle in tequila sunrise (orange). It does not lock, but I've been teaching him proper handling skills and being careful not to demonstrate any bad habits myself.

So far, at four Y-Tribes campouts, I've applied seven band-aids to whittling kids, but none to my son. Teaching the skills and providing supervision as they become second nature seem to be most important.

Not one kid was cut because of the knife inadvertantly closing. Nearly all were in the wood-holding hand. The deepest cut was in opening the knife. An 8 year old got the knife open slightly by pinching the back of the blade, but then tried to open it the rest of the way by placing his fingers on the business side of the blade and sliding it open.

Oh, and the knife is "mine" right now. I plan to gift it to him this Christmas after he has used it for a year as "dad's knife". I hope that he will value it more and be less likely to lose it. I even have some pipe dreams of him passing it along to his kid some day.