table1 records contain a large number of text fields with
unicode, indexed, allow zero length, required, all set to "no".
Many of the fields are zero length, so I assume allow zero
length will only apply when new records are inserted.

I copy structure only from table1 to table2 (no primary keys).
I use an append query to copy all data from table1 to table2
and it works for all records, despite the no zero length rule.
Why?????????

I copy structure only from table1 to table2 (no primary keys).
I add indexing or a primary key to table2 before the append and
then remove it, and then when I try to use identical append
query to copy all data from table to table2 I get warning:

didn't add xxxx records due to validation rule violations

It's almost as if the no zero length rule in table2 doesn't work
unless some change is made to table2 before appending records.
How can I make sure validation rules always work for an append query?