That's cool, but nevertheless it's still a thing that's done in many places. The safe charge is usually under $2 a night...not enough for most people to complain about, but if you multiply that by the number of occupied rooms on a given night, times 365 nights in a year...and you can see that it can be a significant revenue source for a hotel. If the upfront cost to install a safe is, say $300...then it's basically like printing money after the first year.

I've generally gotten it waived, and sometimes the desk clerk claims it isn't charged anyhow, despite the what the sticker on the safe says.