Dress code: "Religious neutrality". Can employers require staff to leave headscarves at home?

The Advocate General (a senior lawyer who advises the European Court of Justice) has released her opinion in a case concerning a receptionist dismissed by G4S for wearing an Islamic headscarf.   G4S had a strict dress code which prohibited any visible symbols of religious, political or philosophical beliefs.   Surprisingly, the Advocate-General's view is that this dress code is compatible with EU discrimination law.   She stated that it is legitimate for a public-facing business to impose such a dress code as part of their corporate image of "religious and ideological neutrality". 

The opinion is surprising and has some worrying implications.  "Neutrality" in this context surely means no more than treating all customers and members of the public fairly and without discrimination.  Would a member of the public really assume that someone wearing a religious symbol wouldn't treat them fairly?  Or that the company they worked for necessarily shared their religious beliefs?   And even if some members of the public would make those assumptions, should a business be permitted to pander to such prejudices?   

Employers should be wary of relying too heavily on this opinion.  First, it's not the ECJ's final ruling on the case.  The final ruling will take several months to come through.   Second, it seems inconsistent with the European Court of Human Rights' decision in the case of Nadia Eweida, a BA employee who, the ECHR ruled, should have been allowed to wear her cross at work.   Finally, while the employer may succeed in the legal arguments, there are clearly reputational implications for businesses which are accused of discrimination.  Dress codes which embrace diversity may be less likely to result in discrimination claims and, I would argue, are more progressive.