This is why I have invented the Gutter Grabber safety device, which is now patented. In fact, my fall protection device can be worn on your belt and applied in about a minute and a half should you choose to use it after climbing up the ladder. It uses 2 uniquely designed rubber blocks that you place between the ladder rail and the gutter, eliminating any side to side movement as you mount the roof. It also uses a hook with lashing strap that, working in tandem with the rubber Gutter Grabbers, keep the ladder tight to the gutter once you are on the roof and need to grab the ladder rail when mounting and dismounting. In fact, it has one hook for open gutters and another hook for gutters with leaf guards. It also prevents the ladder from an accidental pullback or kickback. Simply click the carry packet onto your belt when you arrive at the work site and take the "Gutter Grabber" out of the carry packet should you choice to apply it when you are about to mount a roof in a situation that might pose some risk.
Ladder safety devices, particularly ladder safety equipment used when an extension ladder is placed against a gutter, have trade-offs. My device emphasizes convenience of using the ladder safety device. I understand the psychology of the contractor placing a ladder against a gutter to mount the roof above it. He is a risk-taker to some degree; otherwise he wouldn't be in that business. He will take calculated risks to mount the roof above the gutter without ladder safety equipment if he believes the chances of losing his balance without it are less than one in a thousand. Many times, it is hard to assess the risk until you are about to mount the roof. Having the ladder on gutter safety device on your belt makes it more conducive to apply it than if you have to get down from your ladder to drag it out or your truck. No matter how effective and expensive that ladder safety device is; it will have no impact if the extension ladder user decides to take the calculated risk to mount the roof ladder safety device free. So, my ladder fall protection device is superior to others regarding the convenient-to-use metric.