Security is risk management.
Running Trusted Solaris doesn't matter if an attacker physically steals the entire server. A company that does 5 billion dollars a year in online business can probably afford a few million in losses to fraud and theft. Problems Security is a process You only need to make one mistake or leave one flaw for an attacker to get in. Regularily scan your network for open ports. Regularily scan your servers with intrusion testing software such as Nessus.