Demarc in FTTH ?

What are you thoughts about whether FTTH GPON systems have a demarc or not ? Would it be the ONT ? (since beyond the ONT, the end user has no ability to test the line). or should FTTH be viewed more like DOCSIS systems where there is no official demarc ? In Canada, the telcos charge a "DMC" charge if they visit an end user's house and find the service is fine at the demarc (indicating problem in within customer's responsability). So finding out where responsanility ends would be userful. Any thoughts would be appreciated. Also, since the ONT is generally proprietary to the telco who made decisions on GPON deployments, does it make sense to have the ONT in the customer's responsability ?