No question. That's ridiculous and I'm glad you called.
Easy on the 'toothless nascar' wisecracks though. I happen to enjoy racing.
Here...you have strong suspicion re: DWI. You, however, didn't see 'the crime' (him drinking) as with the first scenario so i wouldn't assume 'obviously drunk.' I've seen a few medical situations where folks were pulled over and their erratic driving was not related to substance abuse. MI and partial seizure were two that I was directly involved in and I've heard many stories. Psychosis etc.
Regardless, good call on your part. The person either needs help or, as you thought, is bombed. I'm not disagreeing with your assessment. Occam's razor is well utilized here. The simplest explanation is probably correct.... and he's 'probably' bombed. I'd withhold judgement, though, and let the police work it out.
Both of these are good calls.