Just droped off Vibe at dealer for some repairs due to hail. Watched one of the inspectors step off onto roof. Walked down both sides and center. He looked to weight 225 to 250. Another tech said the walk on the roofs all the time...just dont jump up and down.
Also drained HW tank. Released pressure on safety valve, then removed the almost year old anode rod. Had bunch of build up on rod but it was all soft. Wiped and scraped junk off. Pressure washed inside and got lots of scale out of tank and off, I am sure, of the heating element. Taped threads and reinstalled rod.
Do not know the exact roof weight limit but it can easily support people working and inspecting...... No problem there. People were on the roofs at the factory as well.
I have seen everyone from inspectors to, repair people to employees pressure washing all the time........ I have been on the roofs of all of our campers at one time or another.
My dealer told me that the Vibe roof is walkable “in certain places”. But like you, I see the techs walking all over the thing. I’m very careful when I’m doing maintenance.