It seems to me that somebody -- Bill Rice? -- wrote a piece a few years back about how bribing maitre d's is a New York practice that, by and large, doesn't really work in Chicago (vs. bribing policemen, which definitely used to).
I did a quick search and didn't come up with it but along the way found this
article about lying your way to a table, which I know happens. Someone I know named Smith used to make reservations under a different name because, he said, otherwise another "Smith" would steal his table. And more than one restaurateur told me about someone else trying to impersonate a local food writer.