There have been many studies that demonstrate that people have a lot of problems to judge themselves and they are incredibly partial when it comes to their actions, basically, they can easily find fault in others but they cannot do the same when it comes to themselves, so it is not surprising that a person could be obviously addicted and anyone around them saw this but the person which is suffering through this problem does not realize it, even if the signs this is the case could not be more clear.
The inability of people to judge themselves and their actions accordingly and fairly without biased judgement is what drag many into the possible situation they experience sometimes and that is what most of us must have to come to term with and being able to stand in the right position to make the right decision and to place ourselves in a position where our actions will not push us into something that we may not likely be comfortable with it outcome at some point.
First thing first since we know that sometimes we allow ourselves to be carried away by our inability to refrain from excessive action so for that we have to make a pre-plan of what we follow and how we manage to follow them fairly.
I believe the first point of the OP is what we need to abide and be firm with ourself.
Because if we will set the funds that we can use for gambling and stick with it, we won't have much problems.
But the dilemma of most gamblers is that they keep on going even if they exceeded their set limits.
Hoping that they will recover such losses up until it is already too late to get out of.