You have to be really, really careful when you run a creative competition on the internet, especially one where customers have access to your assets. Sadly, McDonald's New Zealand was taught this lesson only recently, with its create-a-burger campaign quietly shut down after being overrun with, well, tasteless jokes.
Here's a selection of submissions from that thread, immortalised in screen-cap form.
The company's Kiwi persona was in the news not long ago after sticking unsecured NFC tags under its restaurant tables. I think it might be time to lie low for a while, if that's even possible for a business like McDonald's.