When the drains backed up in a city centre sports block, the cause turned out to be a mix of rubber and fabrics, paper and plastic: wet wipes, a variety of tissue papers, sanitary pads, disposable (haha) nappies, Q-tips, various forms of bodily output, plasticised paper (burger wrappers) and condoms were to blame. It wasn't a fatberg, as sewer techs call the stuff they routinely have to remove, but the effect was the same. If disposable nappies aren't actually disposable by any sensible definition of the term, what about using "flushable?" That's a case that has just come to court.