What initiates the creation of a DP?

Dave Jacobowitz wrote:

I fly out of Palo Alto, CA, and I have never heard an IFR clearance
read over ground whose route section did not start "when able, right
turn to 060 with 1 mi of the airport, radar vectors san jose, v334
sunol ..." My clearance starts out this way whether I file a flight
plan to the east, north, or south. (I haven't flown to Hawaii yet, so
can't say what I'd get going west. ) It also does not matter if I
file /G or /A.

FWIW, a usual "de facto" DP out of CDW is similar:

Left/Right to 180, vectors to Lanna...

except we're being directed to an intersection. What makes this odd is that
this is given even to /U and even though one of the VORs forming the
intersection is roughly between the intersection and airport.

This is just for westbound, though. We've different "de facto" procedures
for other directions (southbound is fun; one passes directly over EWR).

- Andrew