> Also Europeans are not, I think, accustomed to asking for salt, or ketchup, on already seasoned food.

Not all us Americans are, either. The only time I can remember asking for such things is when the server forgot to provide ketchup for some fries.

If a restaurant doesn't season the food adequately for me, I'm not going to fix it at the table. I'll just factor that in the next time I decide where to eat.

Also, the vast majority of restaurants I've been to use far too much salt during cooking anyway.