Correct. Since 1990, I have had business and personal AMEX cards and never co-mingle charges. It would be irresponsible to do otherwise.
Sorry to sound like Bill Clinton, but it depends on how you define “personal.” My company issued credit cards to my employees. There have been many instances of what some would consider “personal” expenses charged and the company covers without reimbursement. If they are on a business trip, they may charge their meals whether with clients or not. They may also get incidental items at Walmart or a grocery store if they feel necessary. Again, this is during a period of (usually) company time and travel, if after hours. Anyway, an outside accountant reviewed all charges and only on a few occasions did he have any questions. Even fewer times did we ask for an explanation. On only one occasion that I can recall specifically (there may have been others I didn’t know about handled between the accountant and the employee) where I told them they needed to reimburse and that was when they mixed alcohol and a meal — a company no-no, but hardly the crime of the century.
I bet if you review those statements, you’d see something very similar to what Rubio had.