Here is a script for making all necessary objects:
CREATE TABLE TEST ( ID INTEGER );
CREATE DOMAIN TEST_DOMAIN AS INTEGER CHECK (EXISTS(SELECT * FROM TEST WHERE ID=VALUE));
Now there are 3 problems:
1) Server didn't create any dependency
2) I can drop table TEST without any problems (think because of 1): DROP TABLE TEST;
3) After table was dropped i can make backup and restore without any problems. I think server should show some message at the end of beckup or restore log...