Of course it also depends on your definition of carols.   In my SATB impromptu group (we did our house-to-house caroling last night) we define it really loosely.

We do everything from Joy to the World, We 3 Kings, Silent Night (we did one verse in German after the English) O Come All Ye Faithful (one verse in Latin after the English), Gaudete, etc. to I Heard the Bells on Christmas Day, Have Yourself A Merry Little Christmas, Carol of the Bells, to Winter Wonderland, White Christmas (including the verse), Jingle Bells (all the verses), I Saw Mommy Kissing Santa Claus. etc.    We take all requests and are rarely stumped--last night when I thought we didn't know a request, I was proven wrong.

As far as I'm concerned, entertainment--and inclusion-- is part of the deal. Why not give the folks what they want--and let them sing along to anything seasonal they ask for?