Well..I think that that is an ecumenical canon (from one of the seven councils). Also, it was passed in fear that those who no longer attended had betrayed Christ and gone back on over to the pagans (i.e. Roman authorities) thus putting the community at risk of being "outed" to the authorities
As I recall the canon does add exceptions for the infirm and those who are travelling or have difficult business. If one must work Sunday on a regular basis (the proverbial diner owner), then one has a good excuse.
I wouldn't consider a soccer game or washing the car a good excuse, but each will stand or fall before his own master.
I've often asked folks to be sure to come once per month, without fail, even if just to a Bible study or other mid-week function. People can grow in their faith. It is a journey. We want them to come to the conclusion on their own that they need to come to worship regularly.
