This is certainly a case by case scenario. As Snatch previously mentioned, in the automotive industry it is generally accepted.
In contrast, I work for a telecommunications company in a regional operations role, which quite frequently puts me in front of a lot of C-level executives (CEO, CFO, CIO, COO, etc). In this scenario, the company expects and demands that tattoos be covered. I happen to agree with this since I am representing the company's image... and they sign my paycheck.
Like I said, it's a case by case discussion. BTW, a lot of those C-level executives have ink of their own, but they keep it covered as well.