The shame of throwing the used towels/bedding/linens in the bathtub/jacuzzi, although, well intended, if the tub was not used, the presence of the used linens in the tub/jacuzzi should prompt a complete “clean” of the tub, which, for the jetted tubs, is a big/time-consuming deal.
For the resorts that have outsourced their villa-cleaning to an independent contractor, those teams are paid, based on production, and the number of villas that they turn. So, I’ll leave to your imagination, the likelihood of their thorough cleaning of the tub, after an otherwise unused tub, has had used towels/bedding/linens thrown in it.