To all those who may be a bit worried identifying the Pope by color, Church authorities directed those clerics who may be in Rome (Maybe in the Vatican only Im not quite sure) to use a none white vestment. So a Dominican may have to use the black one when in Rome.
Some Bishops in countries with a hotter temperature may wear like the Pope but would wear the purple (red if a cardinal) zucchetto and would have purple (again red if a cardinal) trimmings and/or buttons. Their clerics instead of the usual black may also wear white.
Dont worry, the Pope's head will always be white when His Holiness is around

And those who are invited to a Papal event are instucted what to wear anyways.
There are some who make a wrong kind of zucchetto where it really looks like the one worn by Jews. A zucchetto is a skull cap, it is made in such a way that it "grasps" the head of the wearer. Poor clerics
I guess thats my share.