[doktrin]

A few points :

1. Getting re-admitted to ones alma mater is simpler than a new school (given that these are adults going back to school who may well have moved and established families, their alma mater quite possibly is no longer an option)

2. How many credits were waived? This is a pretty serious sticking point, as anything > 2 year full time equivalent becomes a major time commitment & investment. I would also point out here that this can vary significantly by institution, unfortunately.

3. Many undergrad classes don't support a fully flex part time schedule (or, severely limit their evening & part time options). This becomes increasingly important in this scenario.

While there may or may not be an admission-department policy or stigma against second undergrad degrees, the system is by and large certainly not geared to encourage it as of present.