Earlier quoted context omitted.
The aforementioned approach is recommended to avoid spreading flu virus, and other winter time bugs. If you want to avoid your kids getting sick, I can recommend getting them a flu vaccine. Probably safer than relying on a faucet containing the exact amount of virus you need to develop antibodies.
> The aforementioned approach is recommended to avoid spreading flu virus, and other winter time bugs. Citation needed. I've never met the "do not touch anything dirty after you washed your hands" and "close the faucet with a paper towel" (!) as a recommendation against spreading flu virus. Especially if by "dirty thing" you mean the faucet handle.
(danish, pdf) http://www.ssi.dk/Smitteberedskab/Infektionshygiejne/Hent%20...
Edit: That one is not specifically for flu, but too avoid infectious diarrhoea. We had a similar one at my job, specifically targeted against viral infections.