I'm working with the streets within the 1910 census districts of Tacoma WA right now, and was reintroduced to a scandal that occurred with that enumeration.

Apparently, blank census sheets were printed up by private individuals, and blanketed over Tacoma. These filled in forms were then turned in to a point person, who divided them up among some of the EDs, and who told those enumerators to include them as residents who were missed ... without any verification. They were mostly put down as lodgers but families were fabricated as well. These names usually appear at the end of the census pages within an ED.

In 1900 there were about 38,000 people in Tacoma, and in 1910 the initial count was about 116,000. The census bureau went through the sheets and threw out over 30,000 names. Some of these disowned people were shown as living on vacant lots. In other situations 110 Italians were shown from a single laundry, and 100 others living in a tiny lunchroom.
I can find some historical articles on this, and legal proceedings were carried out against a number of people, but I can't find any more information on the outcome of their trials.

It's amusing looking through the 1910 Tacoma census sheets to see how one tries to find "homes" for 30,000 extra people.

One problem though, is that if one does a search on a name, and finds a match to a person in Tacoma in 1910 ...but it's not quite a good match...but good enough..... there is no warning on the Ancestry site that the name was considered bogus. Unless one sees the "O" written over the original entry (meaning omit vs an X which meant keep) and asks further questions, one wouldn't necessarily be aware of the problem.

An interesting situation...

Joel Weintraub