Why not? I am all for the elderly growing old as disgracefully as possible.
Age is only on the outside , never in the heart and mind.
If golden oldies want to wear thongs , what is it to do with you.
Maybe................just maybe, that this woman who bent over and showed her thong was wearing it over the top of normal knickers. And all you saw was the top of the thong.
=-)
Sorry to lower the tone; but the lady may've been wearing an old fashioned sanitary belt to hold up her incontinence pad.
Does that make you feel better, or worse?