If that's American, I must have been American all my life! Funny I'd never noticed and nor had anyone else. 
Haven't we got both usages in English English, then? I think of them as the Perfect tense and the past historic, though I don't suppose those are the correct names. Anyway, I'm sure it's allright to say "I just spilt" as well as "I have just spilt". The first is less immediately in the past than the second.
Besides, where on earth did those Americans get it from?
#nevercouldspeakproper
