It's a really interesting question. I don't believe in all the same rules obviously, for reasons mentioned above.
However, when it comes to food I basically believe that if my child can't have it, then it shouldn't be eaten in front of him/her. (I know the OP doesn't do that.) So we're not talking about a difference in philosophies about rules in general, just about that specific rule.
I personally believe that sharing food is a central experience of human beings and human nature, and that although some things should be consumed in moderation (and sometimes adults need to police that) that what I value
about eating as a social activity is that it is shared. And I do think that for the same reason that a child might eat a whole box of cookies (not having the capacity to think ahead), he or she might feel waaaaay more left out not getting a french fry than it would seem on a logical, adult level.
So although I might only allow my child one french fry, if I were having some, I would allow him that taste. I'd also allow/expect him to have one taste of brussel sprouts too. :-) My son's 19 months old but this is how he's been introduced to everything in our diet, pretty much, except peanuts and other choking things, and lunch meats and that sort of thing (which we just eliminated from our diet too).
In other words I might limit quantities of certain foods, but I wouldn't limit them completely. And once in a while I might not even do that. I'm not totally sure yet. For me I think the social nature of food and my desire to include my son in all the wonderful cuisines we try out trumps any damage done by a single fry, a very small piece of chocolate, etc. And really I should exercise moderation for these things too!
We don't drink pop, so that's not an issue, but that's probably my hot button - I would be glad if my son never ever drank pop, but he'll come across it some day. I think we'll treat it like dessert at that point.
For wine and coffee I'm more strict, but I think once he's 8 or 9 a *very* small taste might be ok then.