I think that the BBC story is off a bit in their "tip suggestions." I tip delivery people (as in, delivering me food, not UPS or something, obviously) more like 15-20% and never less than $3 even if the bill is only $10. I'm not really sure what the standard is, but I'd imagine that's about right. The delivery people have a much harder job than the servers--they have to ride their bikes out to you, often in the rain or other inclement weather, and usually do much less volume than the servers. I also think that the standard for waitstaff these days is more like 18-20%+, not 15%, but that may be an NYC/East Coast thing. Remember that the server doesn't keep the whole tip--they tip out the busser/runner and bartender, at the least.
For the record, I wait tables and I NEVER say "that is AWESOME" and I don't assume that the table wants to be my friend, unless there is some indication that they do. Nor do I ever tell anyone my name unless I'm asked (and it kind of annoys me when people ask my name unless we've already established a rapport, it often comes across as condescending. I still tell them, obviously).
I used to work in a restaurant located in a tourist-y part of Manhattan and I'd be lying if I said we didn't groan when we got a table full of people with accents. We usually assumed that the Brits/other foreign native English speakers would at least tip *something* and be more likely to be familiar with the custom (although they were rarely generous tippers). But other foreign tourists were very much a crapshoot and we hated taking those tables.
Legally, in NY State, the only acceptable forms of ID to drink are passports, US or Canadian driver's licenses or non-driver's ID cards and US military IDs. Foreign driver's licenses, etc, are not acceptable and sometimes, when I was busy, I would exploit that to get the foreign tourists to leave when presented with their driver's license. To be fair, some European driver's licenses are super dodgy looking (basically unlaminated pieces of paper) and it wouldn't be hard for some American college students to forge one and put on an Italian accent or something. But mostly, I wanted them to leave (which they often did) or a least keep their bill low (no booze) so that I would lose less money on the table (lower bill means a lower tip out, since the tip out wasn't based on the tip they left but on the total sale).
Part of me would just rather make a living wage and have benefits and part of me likes the system the way it is.