Completely oblivious and ignorant here: If a company has no official office in Europe, how does this affect them? All advertisement and business focus is say only in the US, is it business as usual? What if an EU citizen decides to sign up? Are US companies forced to deny customers not par of say an IP block (half assed method I know, but just speaking in general)?
If you dont have money, materials, or employees flowing through Europe there is very little they could do to you even if you actively flaunted the law. They could always block access to your site, or even try to sanction your business but unless they are willing to invade your country to physically stop you they don't have very many options. There is always the chance that your own government will enforce EU rulings…
If a noncompliant company is going through due diligence prior to being acquired, they be legally obligated to disclose that judgement? Even if they didn't, how hard would it be for an associate at a law firm to check public records about the company?