[hn_throwaway_99]

There is a very long history of jurisprudence over the past 2+ centuries that has done a pretty good job of defining what "unreasonable" means, and there are tons and tons of SCOTUS cases that have dealt with that. The basics, though, nearly always involve a judge reviewing the evidence to determine if a crime is probable, and issuing a warrant in that case.

The fact that civil forfeiture is so contrary to all the other definitions of "reasonable" that courts have emphasized over the years should make it a clear violation of the Constitution.