Some alt coins don't even bother making address validation, which is very irresponsible.
Users can easily send coins to a wrong chain, causing big trouble or even total loss. Case in point:
https://bitcointalk.org/index.php?topic=180518.0Bitcoin -- BTE -- TRC
I wonder if there are others.
Why including BTE on your list? You can't send BTE to a BTC (or any other) block chain address.