How do colleges know if you're doing multiple degrees at the same time ?

[nyvrem]

For example, I have an AA, 60 credits done. So I transfer all 60 credits into College A and finish a major in computer science (example)

while doing my major in computer science, I decide to concurrently enroll (using my AA degree) into College B to finish a degree in another major, eg, Business

Assuming I'm paying cash for both degrees (ignoring FAFSA and financial aid)

How will either college know I'm doing a degree at the other one ?

Will there be any serious implications ?