As was disclosed today, several wallets have been found not to handle well the scenario of reverted transactions at zero confirmations. This includes showing an increased balance to the user without decreasing it when a transaction is replaced and also preventing the user from being able to spend other valid coins.

You can test the behavior of your own wallet (either that you use or develop) and read more about it in this new tool: 

https://github.com/KZen-networks/big-spender

Oded