You're right, it was a jam job. I've never heard of a room fee ever. I have heard of 18% gratuity for large parties, which is fine, b/c usually they have multiple servers tied up on your table, and you should tip that high anyways, AND the tip per person is only 18% of each person's dish. so if you buy just a beer for $5, your tab personally is only $5 + 18%, which is fair.
The only time i don't like the automatic 18%, is if the service is crap.
If this is their policy they should put the $250 fee all over their website, poss on a sign or on the menus at the restaurant etc. Then you have the option to opt out, i'm guessing tech when you walked in or when they called you guys coulda said, "Nah, were outta here" but that would've made you look bad. But whatever, crappy operation, i won't go there either next year.