I kind of agree with the UM grad.
You can always remove the catheter and observe whether there is any evidence of urinary retention.
But whether or not to give antibiotic, I'm not so convinced.

The catheter should be removed as soon as the catheter is not needed anymore.
But in case long term catheterization is unavoidable (such as chronic urinary retention of any cause), then the catheter must be exchanged every 2 weeks (6 weeks if it is a silicone catheter)

If there was a recent surgery, there will be a surgeon's note. Patient or family will tell they have undergone some surgery.
Surgery on bladder will usually have a scar. In surgery using cystoscope, e.g. TURP, catheter can be removed. If the patient developed AUR, then just reinsert the catheter.

Some urology centers have day care service, and the patient will be advised to go there directly if they encountered problem. The surgeon or the uro mo will also tell patient what to do...
Unless the patient/family is so dumb until they can't even say a word or produce the surgeon's note, don't even think the pain is related to the surgery, then that's too bad lah...

Wah...
Less than 24 hours, the posts are already 10 pages. I wonder how many pages this topic will end up...