I see nothing Catholic in such actions that totally omit any element of Christianity.
In Ireland and in France and some of the other Mainland European countries, crucifixes are erected and, even, small shrines established.
That is a good Catholic custom.
Faded flowers at the roadside are mawkish and secular.
Throwing flowers at a coffin may have an emotional value but not a spiritual one.
What action could or should Catholics make?
Prayers, of course, but maybe we do also need a physical sign or symbol of grief. But what?
A prayer card encapsulated against the weather? A cross?
Any suggestions...please forward to Eccleston Square (but don't throw them at the Archbishop)