Is it safe to walk on a metal roof of a metal building?

I’m looking to buy a metal warehouse building. The walls and roof are dirty and need cleaning. While the structure is plenty sound, I’m wondering how safe it is to walk on the roof. I was wondering if all metal roofs are built strong enough to support a person walking on it.
For other types of roofs in colder climates, building codes specify a load capacity to hold up under snow. Here in Houston, such support does not apply. As the roof itself is very light, it doesn’t need to be very strong to shed off rain.

Metal Roof