Police, yes-this person is either drunk, distracted or suffering a medical emergency.
Pass, no-as others have said, the point at which you make the maneuver puts you between the offender and a freakin 18 wheeler, no escape options when they veer completely into your lane.
I followed a driver heading east on I-20, starting about 15 miles before the Hwy 69 exit. They were weaving from the shoulder on the right side to almost hitting the concrete divider wall on the left. Contacted DPS with mile marker, direction, plate number and description of offender's car and my own. Never saw the DPS and the driver pulled off to the shoulder and stopped about 6 miles east of Hwy 69 exit.
2014 Race Red Base Model-3.7L, MT82, Tech Package, 18" Black Factory Wheels, AirRaid CAI