Comment by pc86

More than $10k in cash is considered "evidence of criminal activity" in many jurisdictions.

It's one thing to have a few bank envelopes with $10k in cash and a withdrawal receipt in a zip lock bag or something that's pretty obviously non-criminal. It's another thing to get pulled over in a $90/day rental with $15k hidden under a blanket in the trunk. The latter will almost always end up getting seized.