flntstone is old school but I tend to agree with him in principle. A guy shows up for a date in flops and a tee shirt??? It better be a fishing date.
This shows a general disrespect for the woman and would be promptly turned away if he was dating my daughter or niece. I am not so sure about the suit though. Does anyone in the western US still wear a suit other than a wedding or funeral? 108F in AZ? Suits are long gone.
A gentleman in pressed slacks, a nice collared and buttoned shirt, and shined shoes would demonstrate respect and be allowed in to meet the parents before a date with one of my darlings. A firm handshake, look me in the eye while answering questions in conversation, and assurance that curfew terms would be honored would confirm the date. Long after my girls were off to college they still clarified basic dress code and standards of behavior so there would be no misunderstandings. My girls are no angels but public displays of disrespect in either dress, manners or behavior are not an option. A professional woman in her 30s deserves this much respect at least.