Obviously race, appearance and attitude matters but what also matters is where you work. One of my friend was working for Provincial Government as a Permanent Resident and when he was called for interview after test, he had his Provincial Government ID hanging in his neck that ID and appearance of Government Employee instantly turned CO into a friendly Bus Driver who love to joke around or sort of flatter Passengers. This person never got any CIT or RQ even though he was travelling every year overseas and USA during Winter Vacations.
If you see CO making notes on your form during your interview right after Citizenship Test, be ready for CIT 520 and RQs!!
Another example is a Hong Kong native who was also appearing for Citizenship test when this friend of mine was. This Hong Kong native tried to act little too elite as this lady barely had any accent and this applicant was able to literally put CO into the shoes of a floor cleaner at the Airport. Funny thing was that Citizenship Official was some kind of Ethiopian/Somalian native and this CO was barely sounding Canadian and this Applicant sounded super North American. Perhaps CO felt little intimidated and this elite applicant got CIT 0520 AND RQ AND further request for more documents.
Don't get over defensive during interview when you are interviewed right after Citizenship Test and this interview is not just about verification of documents such as PR or COPR, IT THE MOST IMPORTANT TRIGGERING POINT ON WHETHER YOU WILL GET CIT 0520 and RQ OR NOT!!!
No matter how friendly, head shaking up and down, agreeing CO appears, if he/she is making notes on the back of your form or in his notebook, come home and start collecting documents for CIT 0520 and RQ!!
So the Notion that people who travel USA gets RQ or people who have lots of overseas trip gets RQ or people who come from Uncle Khalid type countries get RQ - is all wrong. Truth is it uncertain who the hell will be sitting behind glass window as a Citizenship Officer. There are things that you as an applicant can control and sort of manage such as being extremely friendly, not being defensive, not taking any question as an offense and just answering the question in concise manner.
One thing is also considerable is that try to avoid any document which was not requested in Test invitation. Some people have tendency to show themselves as how different, how elite, how North American version of immigrant they are! DO NOT DO THAT JUST LIKE THAT STUPID HONGKONG APPLICANT WHO WAS TRYING TO SHOW HER AMERICAN ACCENT TO CO, IF YOU DO SOMETHING LIKE THAT, YOU ARE ALMOST SHOOTING IN YOUR FOOT! Another applicant of same type was working in USA before moving to Canada so this jerk brought all his USA degrees, USCIS approval letters and literally anything that had United States Government logo on them, it also made that CO little intimidated or felt small that he issued all possible RQs.
Only COPR, ID, Passport and letter of invitation to take test is requested, why the hell this clown brought his all American Prestigious Degrees, USCIS letters etc^ Obviosuly he intended to show off so that Somalian Canadian CO who literally looked like Night Shift Donut Sales Man at Tim Horton got pissed off and he issued RQs and CIT 520. So be normal and just try act like what will be expectation of a person from country of your birth^
All above examples teach one thing try to act like how a person would behave from your country of birth. Trying to sound American or British or someone else will not help here.
Infact there was another Pakistani Uncle Khalid type immigrant in late 50s who came in flip flop and pajamas and he literally acted before CO so humble, as if you go to a curry restraunt and servers would behave that he really satisfied the ego of Citizenship Officer that he got no CIT 520 or RQs.
What it demonstrates is when you go see CO, try to be super humble, thanksful in certain cases act sort of Bloody new comer. That newness will get you the favor you need.
I think the reason applicant try to show their sound communication skills by American accent or so cause they believe that quality of immigrant and evaluation of language skills by CO is part of their application and infact it is but it can hurt if your acquired eliteness is applied to a wrong person. There are people who appreciate a newcomer's attempt to sound Canadian/American and there are people who get upset if they see accent is not aligned with Country of Birth and Race so just make a sound judgement by observing CO's personality, tone and then apply appropriate technique out these two; bloody vs elite newcomer ready to join North American Society!