Please read http://stackoverflow.com/questions/5480131/will-python-systemrandom-os-urandom-always-have-enough-entropy-for-good-crypto

/dev/urandom can indeed run out of entropy if it is called repeatedly.
Here we call it only once, when the wallet is generated, so this cannot happen.

The only risk i see is if your wallet is created as part of the OS install on a very simple device. Correct me if I'm wrong.