nah that's fair enough mate. I can understand your reasons completely.
what people have meant about the fliplines being passive (i apologise if im emphasising something you already took onboard) is that once they are around the tree, they require little input. if you 'gaff out' (climbing spikes disengage from tree), then the flipline will stop you falling away from the tree, and if you wrap it a full turn about the trunk, it will choke the trunk and stop you from falling. I appreciate you have this nifty fall arresting lanyard thingy so I can only really play the 'hands free' when stationary card.
not to mention they give you another means of attaching yourself when limb walking. it's just added security all the time.
I would still be inclined to think that once you try climbing with two suitably stiff fliplines, and use 'alternating lanyard technique (where you approach a limb, and clip one flipline above it and one below so that you are never detatched from the trunk) you would be hard pressed to regard the axes as easier (far easier this way on your arms, with the leg muscles being the biggest and most powerful in our bodies), and if you find it easier with the axes, fair enough again, but is it 'safe'. a little bit more effort is a fine trade-off for wellbeing in my book, but anyway, i'll stop rambling and leave this to your testing period.
I can indeed see the merits of your cammed lifeline. I really can. I think the problem is, traditionally, tree guys dont trust mechanical rope access doohickeys because there is a very specific way that they climb and move within a tree. as microcenders et al become more popular, who knows, its day may come, but it probably wont
