Non-Muslims are often afraid of visiting Saudi Arabia as they believe that they are going to be mistreated but this is not the case.
Saudi Arabia is a home to many expats be it Muslims or non-Muslims. One of the non-Muslim friends narrates that he has been living in Saudi Arabia for 6 years and never has he encountered unwelcoming behavior.
He has always been treated with kindness and respect. Be it police, locals, expats in KSA, or his colleagues, all have been kind to him and have always been helpful.
None of the services were denied to him due to his religion. He was free to practice his religion and to live in freedom. Be it legal work or a casual party, he never felt an odd one.
The US national living in KSA further narrates that only once he was not allowed to enter a mall because he was wearing shorts which is not a public dress code in Saudi Arabia.
Nevertheless, the police were not rude or mean to him rather asked him politely to leave as he was not following the dress rules. He says that US police had been much harsher to him and expats when they were not following a rule.
I myself have many non-Muslim friends living in Saudi Arabia and none had encountered a discriminating behavior towards them. The religious police would kindly tell them to follow up on the rule. They never faced harsh or abusive language from them.
However, the new wave of modernism has fixed this problem as well. The non-Muslims and Muslims in Saudi Arabia have now been granted more freedom and liberty.