There's a difference between respect for the in-laws and a meaningless gesture. Are you really going to skip out on asking your girlfriend if her father says no? Probably not. So it is, by definition, a meaningless gesture. And I contend that you can build a rapport with your future in-laws without pandering in the form of "seeking permission" to marry their daughter. I didn't ask my in-laws, but I'd gotten to know them well enough that they had pretty much already accepted me into the family. Why do I need verbal confirmation beyond that from people who aren't even involved in the union? Their opinion has no bearing on anything, even if they are in favor of it.
Granted, I'm a little weird... I got an angry phone call from my mother several days after the engagement asking why she had to learn about it from my fiancee's Facebook page, so clearly I'm not big on strange family traditions like "communicating."