I'd be careful with the blocking people in if I were you.
A/ It could be illegal (parking in a M&C bay isn't)
B/ You could end up with some 1/2wit reversing into your cars side to try get out.
C/ Unless you know who you are blocking in they could be a big, black belt owner who wants to tear you limb from limb when you come out!
They can give it a go on a rather battered C180. I suspect my car is already in worse nick than theirs.
To be fair though, the only time we did block someone in was because they'd parked in a blue bay (my mrs is disabled). I told staff on the way in what I'd done and why and said they could page me to come out and shift it once they'd had a go at the person.
When I did go out they huffed and puffed but said sweet FA as it totally served them right.
m.