In India, it's very common to say...
"My in-laws have come these days."
This simply means that the speaker's parents in-law have come. The use of in-laws with the word 'law' pluralized is incorrect. I know that because we say sisters-in-law and not sister-in-laws to mention more than one sister-in-law.
Imagine a game wherein married couples are made to sit on one side and their parents on the other. So now, at one side there are 'coupleS' and on the other side there are 'in-lawS'.
I'm adding 's' to make 'in-law' plural the way we make other words/group plural - 80s, CEOs, MDs, scientistS, brotherS, sisterS and the like!
ONE PAIR OF PARENTS-IN-LAW + ONE PAIR OF PARENTS-IN-LAW = PARENTS-IN-LAWS?
Again, the last letter 's' is NOT pluralizing the word 'law' but indicating more than one pair of 'parents-in-law'.
Is that okay to say or write? in-lawS that way?