Unfortunately, the biggest dinner bill I ever got while drunk was real. In fact, it is probably better that I was drunk. Had I been sober the shock probably would have killed me.

I've worked in restaurants before. They don't overcharge people by changing list prices, but they do push more and more stuff on people who have proceeded past the tipsyness line.

There are many sophisticated ploys to get money from you in restaurants and you don't have to be drunk to fall foul of them. Some of them are almost scams.

The wine upsell trick - you order wine from the wine list. The waiter takes the wine list, as he does he suggests an alternative wine that may better compliment your selection of food - when you get the bill you find out that their selection was 3x the price of yours - happened to us at the Hilton in Auckland - not very happy.

the tip on tip - happening alarmingly more in some restaurants in London and on one occasion made me feel decidedly uncomfortable. A mandatory service charge of 12.5% (not even discretionary) is stated on the bill. When the waiter arrives with the bill it is scrawled in a barely legible fashion, the waiter then hands the credit card machine with the tip screen on - when I explained I had already paid 12.5% on food and wine it was explained to me abruptly that staff don't get that. I explained that wasn't my fault, but I felt quite uncomfortable.

don't be a cheapskate scam - you arrive at a swanky restaurant (several in London do this) and are immediately offered champagne without any explanation of the cost - it puts one on the back foot because one may feel uncomfortable asking "how much"? I've been charged over £25 a glass on occasion for that welcome drink.

I'd say that the bill is over about 15% of the time, and under about 5%. I rarely drink, so that's never a problem on my end, but have run into waiters changing the tip, and of course plenty of extra stuff on the bill that I didn't order.

I worked in a service business and for many jobs we had no set price. If things were slow, we'd charge a bit less. If it was in the evening, it might be 3x the price.

What I learned from that is to always ask the price. I don't see that it hurts in any manner.

Almost got caught in Vancouver (my home) during the Olympics. Dropped into a place for lunch with a friend and got nailed by a very high mandatory service charge. Almost tipped on it to boot as it was not obvious and they definitely didn't highlight it. Very unhappy with the place and won't be back period. You don't charge a "service charge" for 2 people.

Some restaurants add mandatory "service charge" to any order (some menus don't bother to show this) - you only learn about it when the bill arrives. Now the best part: waiter's "poor" eyes show he expects a tip. What do you do? (Let's omit situations when the service was outstanding - we're talking about routine, proper, standard service). Do you ignore his begging, expecting eyes... or do you have soft heart and pay a tip over the "service charge" ?

No, the reason he's waiting is because he couldn't get a job as an actor.
Silly to reward bad acting.