Yep, when I visit my mother, if I don't abide by her rules of... never ....
cross on the stairs
put new shoes on the table
look at a single magpie without bidding it Goodbye (although the toon fans usually hang out in multiples)
open an umbrella in the house
spill salt without throwing some over your shoulder (something which I think, is potentially a dangerous thing to do)
So to me, there's some proof of bad things to come (usually in the form of a hand across the ear!)