I would be careful about the edge protector use on any horizontal edge. Horizontal seams and edges such as the trunk or hatch edges are most susceptible to rusting because water tends to remain in those areas.
Almost all seams in body work such as those where plastic bumper assemblies meet the metal body are now made at an angle to encourage water to flow to the lowest level.
Just look at the rusting patterns on cars and light vehicles on the road for a few years. The first rust always shows up on horizontal bits - and the bottom of doors, trunk and hatches. That is where water and salt gets to do the most damage. Drainage is key prevent the earliest damage.
Coastal regions can see corrosion issues on horizontal surfaces like hoods and roofs where salt laden sea spray settles on surfaces. Again, washing, rinsing and drying is important.