Is an empty parking lot on a multi-family a red-flag?

[Ron Read]

Seller claims 6 of 7 units are rented, but none of the pictures in his listing show a single car in the parking lot.  I'd expect no-matter the time of day this shouldn't be the case.  Am I paranoid?  Should I even waste the 90 minutes it would take to drive out and check out the neighborhood for myself?  The deal looks 'okay' but not fantastic if all his numbers are right,  which doesn't leave a lot of room for error.

[Ryan Murdock]

Either:

1. Everyone is at work.

2. It's a C/D class property and everybody is home but none of them have cars.

3. The place is vacant.