I know the boards will often suggest opting out (which I did) -- but I've always been unclear as to why. Many of the posts related to this suggest this is one of the first steps when cleaning/rebuilding credit, and imply that it somehow helps prevent collection agencies from "trolling your file"....? Can anyone clarify the actual benefits to opting out and whether it is directly related to preventing CAs from gaining access to info, etc.?
Starting Score January 1, 2010: 640
MrShush - Penfed does the preapproved offers based on credit, with a minimum of a 700 FICO score. I have heard rumors, but have not called Penfed to verify, that they have raised their minimum FICO score to offer preapprovals. They go in cycles... If there is something you want from them, call them.
I have the opt out on my credit reports and still receive offers from Penfed. Again, it goes in cycles depending on a lot of variables. DH gets none. I suspect, many moons ago, he opted out of pre-approved offers. Or it could be that he just doesn't qualify for them.
ShootingStar - Before opting out, I kept noticing inquires on my CR. I would ask someone at the CB who they were and dispute them. I learned that often they were collection agencies. The rep would see that I had no lates, no probs, and she would delete them. Since opting out, there are no collection agency screenings. 
I have no clue if CB actually sell the information to collections agencies, like they do to ccc, but i suspect they do. Your information is pretty much up for sale to the companies willing to pay.
Thanks for the feedback, IOBA! I've always wondered if opting out really prevented CAs from looking for people to pick on. It is encouraging to know that maybe I didn't opt out in vain! 
MrShush - go for it! Another insider note, wait until you have been with Penfed for a year before you start asking for the stars. (At least a minimum of 6 months though.)
By asking, I have raised DH cc from 13k to 41k over the last few years. And we went through some really tough, really tight times with Penfed (and others) when DH was suddenly deployed a few years ago. They grudgingly stuck with us through that time.
In return, I changed my relationship with them. I made payments every two weeks instead of once a month. I started moving pennies over to savings and slowly building that up. I told DH he could only use the cc overseas if we talked about it first unless it was considered an emergency. (Due to the nature of his job over there, we only had one phone call - Yahoo - the entire tour.) I also told DH that his card was maxed out, over the limit which affected his - DH's - mental attitude towards the card. It was the only card he had with him.
We had some pay issues -- uh, like not getting paid all that should have been paid while he was there. With Penfed, I asked for them to raise his limit a very small amount while he was there until I could get the card paid down so it wouldn't report as over the limit and so we wouldn't get charged fees. I want to say it was like a $300 increase and they grudgingly did so. I did not ask for the lower interest rate. I did not ask them to waive fees. They certainly knew what was going on and where he was.
When I could finally scrape together $100, I went and opened an IRA for him, at Penfed. That helped grow our relationship. We don't really contribute to it now...but it's still there and Penfed knows we will be with them for years to come. Every time I call them or go in person, I tell them how great they are and how I love Penfed.
Grow and nurture the relationship.