"Table of Constants" - is this common practice?
Joe Celko mentions tables of constants in a couple of his books. 

He suggests if using a table that a check constraint is added that ensures the table can contain no more than one row. 

CREATE TABLE Constants
(
lock CHAR(1) DEFAULT 'X' NOT NULL PRIMARY KEY CHECK (lock = 'X'),
pi FLOAT DEFAULT 3.142592653 NOT NULL,
e FLOAT DEFAULT 2.71828182 NOT NULL,
phi FLOAT DEFAULT 1.6180339887 NOT NULL
);


Or alternatively a view can be used for a similar purpose.

CREATE VIEW Constants
AS
SELECT *
FROM 
(VALUES(3.142592653,
        2.71828182,
        1.6180339887)) V(pi,e,phi)


Not something I've used much, if at all, myself but always worth having additional possible techniques to consider.

The specific use case in your question isn't something I would consider a table of constants for though. TBH the hardcoded same "hometown" for everyone just seems a nonsensical requirement.