Why cops can seize cash in civil forfeiture but cannot check serial number behind stereo equipment?

2018-02-23 10:22:29

https://en.wikipedia.org/wiki/Arizona_v._Hicks

I look at this case.

A cop saw expensive stereo. The cop check the serial number and found that the stereo was stolen.

The cop move the stereo a bit and get the serial number. The evidence is thrown out of court.

However, I've heard cops can seize cash on even less suspicion.

The mere act of bringing cash is punishable by civil forfeiture without trial.

So why the contradiction?

A cop can seize cash, but cannot seize, or even merely look at stereo?