You Keep Using That Word. I Don't Think It Means What You Think It Means.

Vicars told ‘don’t wear dog collars in public’ over fears jihadists are planning attacks
Worries knife-wielding ISIS jihadists will target churches were raised by experts and revealed by churchmen.

Vicar Rose Hudson-Wilkin

  New counter-terrorism advice is being urgently issued to vicars and churches across the UK this week over fears an attack on British Christians is now likely.

By dog collar, they mean clerical collar. However, I found out that in England, the clerical collar has been called a "dog collar" for centuries. Apparently, changing the name led to the downfall of the British Empire.