[paul51]

If we say we are going to document and then shut the door, how many do you suppose will step forward to be documented?

[Centennial]

Almost all of them will. Documentation would carry the benefit of being in country legally, drivers licenses, access to all employment and other benefits. Without the threat of being deported for being here illegally most all will go for it. After a grace peroid you start deporting those who do not obtain documents.