As a mother and wife of a husband who would never allow such horrors to befall his family (without a fight and especially when weapons were of no consequence), this was one of the most implausible plots I've ever seen in a movie's storyline. What a complete and utter waste of an hour and a half.
Tension, yes! Music that matched the developing tension of the storyline, yes. A family, innocently meeting another during vacation then becoming acquainted enough to invite the other for a subsequent visit, yes. BUT, the absolute nonsensical progression thereafter, NO!
And where are these 5 star ratings coming from?