It is perfectly legal to deposit your money in a pattern as long as you declare it
But that's not the case here. If you have a cash-heavy business, declaring it on your income taxes doesn't protect you against seizure from apparent structuring of deposits. In the last case mentioned, the cash was simply from cashed paychecks, which obviously had already been declared.
It is illegal to deliberately pattern your deposits in order to avoid law. It's not illegal to avoid a DUI checkpoint - but I have also known DUI checkpoints that station officers in nearby neighborhoods that drivers might use to turn around after sighting the checkpoint. Those officers will stop people driving into those neighborhoods and talk with them there. In my state, that's legal. (It is important to note that DUI law varies state-by-state. In PA you must notify drivers before a DUI checkpoint and give them an option to turn off. In my homestate there is no such law.)
I can see that, but the pattern could be a result of legal practices. Shooting first and asking questions later harms good people. The IRS audits very well. If they see a pattern that suggests illegal behavior, they should audit the entity, not seize their funds. I am sure other options could be devised as well.It is illegal to deliberately pattern your deposits in order to avoid law.