trap
I guess that's to protect the home of snowbirds who go to Florida for 6 months and are too stupid to take measures. So, to be hooked up to the town sewers, you need to have a house trap
If they are not around to keep the fixture traps sealed, how is the house trap going to keep water in it? and those sewer guys were no worse than the ones who use a "stock" tape to show that a sewer needs to be dug up. Probably work for the one of the same companies.