I've got to go with Mike and Scotus on this one -- even if folks don't recognise the Clergy tartan, they might not understand why someone who is not a member of the clergy was wearing a tartan for that profession.

Another tartan with a religious association is the Douglas tartan, which was worn by the Cameronian Regiment of the British Army -- the only regiment named for a religious leader, Richard Cameron. The Cameronians were originally a group of strict Presbyterians, Covenanters, who used to worship at secret & illegal services called conventicles. The Covenanters would post armed guards at the corners of the meeting to watch for government forces coming to break up the meeting. Later, the followers of Richard Cameron would be recruited into the British Army to form the new regiment. Up until their disbandment in 1968, the Cameronians would post sentries at the four corners of the kirk on Sunday, and the padre could not begin the service until an officer shouted "all clear!"

The Cameronians were later merged with the Scottish Rifles, and the new regiment became a rifle regiment, so the Douglas tartan, which has quite a bit of green, was chosen. The Cameronians wore Douglas tartan trews.

When faced with amalgamation in 1968 with another Lowland regiment, the Cameronians chose to disband.

Cheers,

Todd