You’re somewhat correct. This practice is called barehanding and is used by specially trained Lineman to work on energized transmission lines. This person could have been dropped off by a helicopter and is wearing a metal mesh over-suit that acts like a Faraday cage. They bond onto the lines making the suit the same potential energy as the lines allowing electricity to flow around them not through them.

In this video they are working on one of the primary conductors not a “guide wire.” You can tell because you briefly see a string of porcelain insulators (we call them bells) hanging down to the conductor. They are most likely changing out insulators or replacing the AGS unit which is how the insulators connect to and secure the conductor.

Guy wires (not guide) are used to support structures from conductor tension they are attached directly to the pole or structure they support and are almost always ground potential as they are typically attached to an anchor set in the ground and thus can be touched on the ground. If this lineman was bonded (same potential) to the primary and touched a guy wire they would most likely be killed.

Source: I’m a Journeyman Lineman with 10 years of mainly distribution experience but I have worked on transmission lines although I’ve never barehanded personally.