Lazy Movie Raters [Netflix Probability Interview Question]

Suppose 80% of Netflix users rate movies thumbs up 60% of the time, and thumbs down 40% of the time. However, 20% of Netflix users are "lazy": they rate 100% of the movies they watch as good!

Given that someone gives 3 movies IN A ROW a thumbs up, what's the probability they are a "lazy" rater?