Wow, every removal? Even a notch and drop?
What if the truck is wayyyy over there, and the tree bring removed is a smallish honeylocust with a a lot of nice scafold branches, one that could easily be climbed by a 10 year old child? Anyway, what if your spikes are back in the truck, and it's a long walk, uphill, and it's 95 degrees out?
How about if it's a simple climb and you nedd to trim two other trees, one just before, and one just after this removal?
What if you are just really good at footlocking, a very safe way to enter a tree, and you just need to scoot up there and knock out the top?
What if that same tree is a hard leaner or has loose bark, and you just need to knock out the top?
The point is this, to say you should wear spikes for every removal is silly. If it's easier, faster, safer, or any combination of these, why not climb without them?