My wife has MS. She'll often park in the handicap spot and go
"bopping across the parking lot" into the store, because, after 10 or
15 minutes in the store, she knows its going to be a struggle to get
back to the car.

She doesn't use a cane (yet), and on many days her condition is
invisible. I understand how you feel, because I know we get
frustrated when we can't find a disabled spot, or another close spot.
However, before you go blocking someone in, imagine how you would feel
after getting out of the store with your legs feeling like cinder
blocks only to find that some &$#**%! has blocked you in. Oh yeah,
then the stress exacerbates the MS symptoms, then the bladder urgency
kicks in.

I'm not singling you out, as I totally understand your frustration.
I'm just hoping that people use a little common sense and compassion
overall, and understand that not all disabilities are immediately
visible.

I am glad you brought that up. I too got the invisible health problems. Some
days I can go bopping across the parking lot. Only to walk around the store and
the pain sets in. Then my cane is not with me. Then I have to sit and
recuperate for a few, then practically feel like crawling back to the car. I
have dignity, and refuse to crawl. So I bear the pain, and walk the best I can.

I swear, if someone blocks me in, because they think I should not have a
handicap parking spot. I would find a way to hit that car, and cause
considerable damage. **** what the outcome is, like a ticket.