I was gonna suggest the cake thing too-but even if you told them beforehand it might still make it less frightening for them all mixed in and baked. It's silly, but I was sort of one of those people. I knew they'd be fine to eat, I wanted to try them, but I was afraid they'd taste strange and I wouldn't like them (and then I couldn't justify getting ducks!). So I started with pancakes, and they were fine, so I told myself "all right, they can't be awful." then I moved up to a breakfast sandwhich made with thick bread and sharp cheddar, and that was fine, and then I was finally ready to try one on its own!
If you're not gonna tell them, go about it casually. Just leave the cake out somewhere with a note to 'help yourself.' If anyone asks, you'll have to admit there are duck eggs-even when you find it silly, you've gotta respect what other adults choose to eat or not. No all-out lying, ok? It's a small difference, but if it's something that really matters to them, they'll ask. As a vegetarian, if I eat something without asking and it turns out there's meat in it, it's my own dang fault. Now, if someone tells me it's meat -free and I eat it but there really is meat in it...I'd be so angry. See what I'm saying?
