Doubt if it will work, but a nice gesture. I think those that would bomb or shoot would consider their fellow muslims to be acceptable collateral damages.

“The Coptic priest was commenting on the now widespread call by Muslim intellectuals and activists upon Egyptian Muslims at large to flock to Coptic churches across the country to attend Coptic Christmas Eve mass, to show solidarity with the nation’s Coptic minority, but also to serve as “human shields” against possible attacks by Islamist militants“

You gotta admire the sentiment, even though it’ll likely get them killed or wounded.