Can't say how safe it is but I have fitted 3 or 4 thinnish rubber bands near the buckle of my RA Marseille-style weight-belt. Had them on there for several years. If I find the opposite belt-end flapping around excessively, I tuck it under 1 or 2 or 3 bands, rather like a traditional belt end retainer loop. I figure I could easily pull it free or break the thin bands in an emergency.
My reason for doing this, beyond those already mentioned, was because I lost my weight- belt when I first started diving, I think probably lost it when I was washed over a shore reef as I came into shore. I say "probably" because I did not feel or hear it release, only noticed when I was standing on shore, packing up.
(Happened at Newton's Cove, Weymouth years ago now. RA dive belt, mixed weights including one or more yellow SCUBA-style weights. Likely very close to low rocky shore in the adjacent park, just below a park bench
).