Many years ago I was working to support a SQL Server based accounting system and had a very troubling issue that was ultimately found to have been caused by case sensitivity.
I learned the hard way that it can matter :-)
I learnt the hard way too: back in SQL 2000 days the default collation was one of the SQL collations (presumably at latin one, but I don't recall which) not a windows collation; but our code was all designed to work with Latin_General_CI_AS (except for bits designed to work with Arabic or other languages using non-Latin alphabets). The installation team managed, despite very clear instructions, to install servers at some customer sites with the default collation (and the wrong default language too, in many cases - they must have actively overridden the SQL server defaults there) and the resulting problems in getting the systems up and running correctly were pretty horrendous. Eventually the installation team was successfully educated, and it stopped happening, but while it was happening it made life very hard.