Of course it is, rule 2: “precautions which may be required by the ordinary practice of seamen”
Take for example a ship with the engine stopped a few miles from the pilot station waiting for a pilot
. In one case there is on the stbd bow a VLCC with CPA = 0 TCP = 10 minutes
Second case same ship with engine stopped but a jet ski on the stbd bow CPA=0 TCP= 10 minutes.
Are you saying the the COLREGS require that each case be considered as the same?