It's an odd sort of ritual they play; nephew cries inconsolably, sis hunts house for his pacifier, finds it, and pops it in her own mouth to clean it just before plugging his unhappy pie-hole for instant gratification to all within earshot. Two minutes later, the happified rugrat crawls away and throws
the pacifier towards the family dog, potted plant, or similar unsanitary zone. Twenty minutes later, Ben cries again, and the whole process repeats.
Sis doesn't want to walk over to the sink every time, and toting around a glass of water is awkward. So, she just sucks on it. Eww...
A few improvements to the baby-plug to save sis from those tasty endeavors:
A portable pacifier washer that seals against the nuk. Plug in, give a shake, and go.
A paging system, like your cordless phone. Press the 'Marco' button and it answers back 'Polo.' This would be entirely more fun than the obvious solution of a wrist band or somesuch, and might serve as a kid-tracking system, at least until the tyke throws it into the plant again.