Re: Who around the USA (not necessarily in Chicago) has "storefront studios?"
WHDM in McKenzie, TN, had a storefront studio, at least back when I was working there in the early '90s. But the back door was about like your typical bedroom door. In other words, it was hollow and could have easily been kicked in. The front door had a window in it that could easily have been broken to gain entry. The front door had a lock on it, but also a hasp that we put a large bolt through at the end of the day. We also kept a washer with that bolt, to keep the bolt from falling through the hasp. One night when I left for the day, I couldn't find the washer. So obviously, I couldn't put the bolt through the hasp. The GM was critical of me the next day for not "locking" the front door.
This was (at that time) a daytime-only AM station, and I didn't really worry about security until the GM, secretary, and sales manager left for the day, usually in late afternoon. For the last hour or two of every day, I usually kept the outside doors locked, to keep anyone from coming in while I was on the air (reading the news or something) and couldn't get to the door. But sometimes the sports director or someone would show up, and I would need to let him in. If I had forgotten to lock the door, I would usually be holding my breath if I heard someone coming in while I was on the air.
The worst part about this was that this station had a "groupie" who would always hang around with nothing better to do, and he would show up at almost any time with almost no notice or advance warning. I didn't particularly like the guy, but management had no apparent objection to him coming around. They even asked me why I didn't "like" him, or what I had against him.
Fortunately, McKenzie is a small town, and the studio was only a block or two away from downtown. As far as I know, they are still in the same building, but they have more secure doors there now, the last time I passed through that area. Probably a good thing, since they are on satellite now, and no one is ever at the studios anymore, even during normal business hours!