To this day I can get into pretty much any rack or room I feel like at datacenters everyone here has heard of. It just takes experience these days and a bit of charm. Plus having a million keys and staff rack combination codes doesn't hurt. These were freely given and simply added to my collection over time, nothing stolen or social engineered.
I've never done anything nefarious with these abilities, and no one I know has either. It's simply a matter of practicality when you staff a 150,000 square foot facility with 2 security guards who have no idea what they are doing.
If I (and many others) had wanted to, we could have caused multi-week/month outages you'd be reading about on the news with 5 minutes of effort. This is basically the status quo for any sensitive industry.
The world turns because 99.9999% of people want to give you a hug vs. hit you. Society falls when that ratio goes much lower.