[ToFundorNot]

There have been tests for antibodies, yes, in NYC. Where is the information for Germany? Italy? California? Two week follow-ups on those test?

Hypothetically speaking, these folk have antibodies, that doesn't mean they're in the clear.

Keep in mind there there are thousands, if not millions of strains of this virus. It is not a static entity, its RNA base means that it can mutate itself to non-existence, or to a more lethal form as it replicates(RNA lacks error correction[1]). That means that even if they have antibodies to a weaker form of the virus, they can still be re-infected by a deadly strain, and be hospitalized, taking up resources for people who are injured, or sick through a normal day.

You have tailing commentary as if I'm disagreeing with your sentiments about lockdown (as of present). I was all for the initial lockdown as the infections needed to be managed (as they were initially miss-managed). Many places are getting a handle on it, and should be able to start opening up over the next couple of months (with social distancing, and random + targeted testing).

[1] https://www.ncbi.nlm.nih.gov/pubmed/9343347 As a note, this is why pandemic need to be stamped out immediately. The more people that get infected, the higher chance it has to replicate highly contagious varieties, which can then replicate to more deadly versions along the pathway(if I understand it correctly).