All the companies that I worked for did provide ear protection but the lawyers could always argue that other causes were to blame - loud music, fire arms, motorcycles...
... which might actually be the case.
If you used the ear protection provided, it's highly unlikely you got the tinnitus from work, except if the ear protection didn't reduce the noise exposition below the "safe for permanent exposition" treshold.
When it comes to potential damage to the ears, not only the sound pressure level is important, but more the time of exposure. While it's safe to have 80dB of noise almost permanently, even 5dB more significantly reduces the amount of time at which the noise exposure starts to get damaging.
For more information, check out this diagram:
http://docs.engineeringtoolbox.com/documents/717/noise-exposure-time.png
Note that an exposition of 95dB for only 60 minutes per day is enough to be in the dangerous area. Note that some clubs usually have the volume turned up to until 100dB.
This is why live music and headphones are so dangerous. You are exposed at a high level and for a longer period of time. This is also why it's so important to wear ear protection at work, even if the sound pressure level is moderate. Due to the long exposure, it's still dangerous.
Also, higher frequencies are much more dangerous than lower frequencies, due to the anatomy of the ear. That being said, a lot of sound guys usually already lost a good portion of they listening capacities, thus turning up the highs to compensate for that even more, exposing the audience to an even higher threat. I've been in so many clubs already and NOT EVEN ONE of them had the highs turned up in a reasonable manner.
(Actually it's one of the main reasons why I love drum and bass music... there's nothing 'up there' that can be turned up... and bass and sub-bass practically deals no damage to your ears even at ridicolously high sound pressure levels)
There's also a sound pressure treshold of emitting sound when it comes to machines. At this treshold, there must be physical means to reduce the noise (encapsulation) in addition to ear protection.