Strange situation on U9 at Zoo. A woman putting something on train poles while wearing gloves

Just saw something pretty unusual on the U9 around Zoologischer Garten.

There was a woman wearing plastic/disposable gloves. She kept reaching into her pocket, taking something out, and then touching/putting it on multiple poles/handrails inside the train.

I couldn’t tell exactly what the substance/object was, so I don’t want to speculate or accuse her of anything. But the fact that she was wearing gloves and apparently applying something repeatedly to surfaces that passengers touch seemed strange enough that I avoided touching the poles.

Posting this partly as a heads-up and also because I’m curious: has anyone seen something like this before, or know what she might have been doing?

If you’re on the U9 around Zoo today, maybe just be a bit careful with the handrails until they’ve been cleaned/checked.

Again, I have no idea whether it was actually harmful just reporting what I observed.