Monkey Island references isn't exactly new - but it's not like there's a huge amount of them in later games.
I've been playing Fable III lately - lovely little game that. One that features a gazillion readable gravestones all over Albion (the world it takes place in). I haven't read them all yet, because there's just so many of them. Usually they explain how the person died. It said:
"Tried to hold his breath for ten minutes"
I'm fairly certain that's a reference to Monkey Island. So there you have it - someone at Lionhead Studios (perhaps Peter Molyneux himself?) is a Monkey Island fan.