According to Solar Flaire :
It would if the live fed through your house load and back fed the
neutral from the grid.

That's only one wire, and it's grounded anyway. The problem is
more along the lines of if you're using a 240V circuit = you're
backfeeding the grid's connected hot via the house load from the
generator's connected hot. Plus the neutral = you're backfeeding
half of the grid feed.
--
Chris Lewis,

Age and Treachery will Triumph over Youth and Skill
It's not just anyone who gets a Starship Cruiser class named after them.