Maybe they read the articles...

Both of your U.S. Senators receive Hustler magazine at their offices. So does your Representative in the U.S. House. Actually, all 535 members of Congress receive the porn magazine every single month, free of charge, compliments of publisher Larry Flint.

From The Salt Lake Tribune:

The magazines have been coming for more than a decade at least. Publisher Larry Flynt says he started sending them as soon as his magazine began publication in 1974, but an Associated Press story from 1983 has Flynt initiating the mailings that year.

Either way, he's not going to stop mailing Congress.

“"I felt that they should be informed with what's going on in the rest of the world,"” Flynt says, deadpanning during an interview: "“Some of them didn't appreciate it much. But, I haven't had any plans to quit."”

Lawsuits have been filed to get Flynt to stop the mailings but, apparently there's nothing illegal about it.

It sounds like most issues hit the circular file as soon as they are delivered, but surely a few copies find their way into lawmakers' briefcases.