[zimpenfish]

That implies 1) the train or bus arrives and leaves at the station exactly according to the timetable and 2) you get from home to the station exactly according to the estimate.

In my limited sample group of one (1), these are rarely true.

[stijnstijn]

The train usually doesn't arrive exactly on time where I live, but delays aren't so bad that I have to wait 30 minutes on average. And if it's a 4-12 minute walk to the station, as OP says, I'm sure they don't need a huge buffer to get there on time. Personally, I just make sure I have a five-minute leeway and I'm good.

There certainly must be places in the world where trains are so unpredictable that the average delay is 30 minutes, but (not having been there, I should say) Menlo Park and Palo Alto sound like places where trains should be a bit more punctual than that?

[no_wave]

But without baking in a 30 minute wait on a train platform how would the parent have been able to make their point?

[kbenson]

Not all trips are to and from locations on specific timetables, such as work. Sometimes you want to go from your house downtown, or some other location. There's still an average wait of half the train interval time. You can wait at the train station, or wait at home and travel closer to the arrival time (and hope you don't miss it), but there's still a wait involved. Sometimes you can effectively use this time, sometimes you can't. Acting like it doesn't exist isn't useful though.