We have hawks and owls so, I put aviary netting over our run. But, I also have a hot wire for anything that might climb or get close enough to dig.
My birds are secure at night while in their coop, so I don't worry about them then. But, hawks have swooped by eyeing them during the day and owls have perched on top of our building out back before we had poultry.
Even if I am home, there is no way that I could keep an eye or ear out 100% of the time. Plus, what will you do when you run an errand? Just throwing out some things to think about.
In my run a snake or weasel could potentially get through. However, we have garters so not really worried about that as my muscovies will probably take care of anything like that.

We live pretty far from weasel territory (ponds and lakes), so I am not super worried about that, but it could happen as they can travel quite a distance from what I hear, but that is a chance I take with my set up.
So, I would take in consideration the possible predators with the set up and what chances you are willing to take.