my wife is about to fly to warsaw en route to ukraine no metal for her though
There is an annual march planed for Independence Day on November 11th in the center of Warsaw. Mostly nationalists, right wing organizations, racists and people who look for fights with vice squad or anyone who crosses their path. I would not recommend visiting center of Warsaw, Old Town, river area, train stations and intercity bus stations on that day and maybe next day and day before.
It's probably the most dangerous day of the year in Warsaw. Normally it's a very safe city with good public transportation and places to visit.