Dear Prudence,
I am a married man with two wonderful teenage daughters living in a tranquil suburban neighborhood. A few months ago a nice couple, "Mike" and "Mary," moved in next door along with their eight children. The family is devoutly Christian. The children are home-schooled, well-behaved, and reserved; and the girls dress modestly. Our families have dined together and get along well. As part of their chores, my daughters do most of the yard work. It's hot here much of the year, and they typically wear short shorts and tank tops or bikini tops. The other day Mike said he wanted us to have a "serious" discussion and told me he caught his boys watching my girls from a bedroom window.
The boys are normal boys, their parents are imposing their values, which I agree with, but Christians need to be IN the world, not OF the world. Big difference.
and He asked if I could please have my girls not wear such revealing clothing if they're going to be outside, as he is trying to protect his kids from "certain elements of the world" and doesn't want them influenced by "overly sexualized displays."
That is not protecting them from the realities of a sex crazed society, it's hiding them.
When I told my wife and daughters, they were offended. Is it unreasonable to ask my daughters to cover up a bit?
It's not unreasonable to teach your wife the real power a woman has when she is modest.
I've had problems with difficult neighbors in the past and feel sometimes it is necessary to make small sacrifices in order to keep the peace. My wife thinks I should kindly tell Mike to shove it. What should I do?
Your girls could be wearing hajibs, and it won't stop the boys from looking. I would apologize to the neighbors for the scantily clad daughters tempting their boys (that is how they see it).
Inform your neighbors when your girls will be doing yardwork, and have them keep their boys away from the window, and apologize for any inconvenience this effort of coperation might impose.
If they won't keep their boys away from the window, then you won't keep your daughters from doing yardwork. I wouldn't say that, but it is important that you keep the peace with your neighbors. You never know when you may really need each other.
Modesty is important because it is the fort that protects the castle, but it is also the frame that enhances the picture.
at your hyperbole here. 
