Curious inconsistent behaviour from SQL Server in windowed function clauses?

Question

Whilst asking another question, I discovered that SQL Server (happens both in 2005 and 2008) seems to have strange inconsistent behaviour when dealing with CASE

Answer 1

The evaluations in your first example will never change.

You are comparing a constant to a constant which will constantly result in a constant.

1=1 will always be TRUE.
1=0 will always be FALSE.