I don't think I should add a link for workshop, as I suggested only the concept. you can find a model quite easy.
No, jump boots can launch you into the air or even reduce fall damage (depending on the server), however: 1)SGM does not have jump boots. 2)Jump boots are incapable reducing the rate of decent.
1) Those "unreachable areas" could be re-marked as reacheble. 2)Props can be used aswell to reach unreachable areas, we just need to add a rule that forbids getting those areas with this item. 3) For most of those unreachable areas, you need to get on top of them from below, and that's somthing this item is incapable of.
They are against the rules because the map makers made them unreachable for a reason and they provide advantages that were not intended. The only one you could get to an unreachable spot within the rules using this is on assault.
it just makes it more forgiving because you'd otherwise survive with 10 hp or be dead if u fell off the fence