The 1.5 inch swim brief

[Bede735]

I've certainly tested the 1.5 brief at my local public pool and haven't had any problems. Not sure if I would be allowed to wear anything briefer than that.
Having said that, I've seen women wear bikinis at the same pool, as in that picture. It's quite surprising how that's allowed, as there must be a chance that the strings could unloosen?