If your hotwife were to wear her anklet routinely at all times, it would eliminate the need for her to make decisions about whether to wear it or not wear it in particular situations. That, in turn, would eliminate the need for her lover to ponder what it means when she wears it sometimes but not at other times.
For instance: suppose your hotwife does not wear her anklet when she and her lover get together, so to speak, but he realizes... sooner or later... she wears it at other times (perhaps as a result of seeing her in public). He might then conclude your wife views herself as having "nailed him down" as a lover, while at the same time she wants other men she views as attractive to think she is available as a potential married lover.
Ambiguity of this nature could lead to relationship problems, it seems to me.