1995 Other Mazda Models weird question

i was wondering something. i have this acura im selling and i noticed the guy had his mechanic take off the cap where the oil goes, while the car was running to see if it had blow back? i am not familiar with this but the mechanic said no

. then me being curious i did the same thing with my mazda while it was running i took the oil cap off(where you add oil) and it was spraying a fine mist of oil out, but not smoke. is that normal? my acura didnt spray anything out. thankyou!