Penalty for missing a mark out?

When I first started racing I used to miss a LOT of marks (as in, at least one per race) and I got disqualified every time. Not sure if that's within the rules, but that's how they dealt with me.  

But, unless it was the last mark of the course that the boat missed, "Finish" is a Definition, not rule 28, and as such cannot be changed?  

at one of my clubs the Ro can be judge and Jury in certain instances, BUT, not when marks are missed out - it is then up to other competitors to protest, or for the infringer to be invited to retire by the RO. In the SI's at this club, it is an immediate DSQ to sail between the inner distance and the committee boat at any time, and the RO can DSQ with no redress at any time during the race, so if you go in the gap on your third lap, you could be out... May not seem fair but everybody sails under the same rules. It is not nice (as an RO) telling someone that they are not ranked as a finisher, because the sailed through the gap!! We do try to remove either the ID or the committee boat to reduce problems!

So it may be that a study of the SI's would give you the answer, if it is not specifically mentioned, then the RO can not DSQ without a hearing, however, he may protest the competitor for not sailing a proper course..

Jon