I agree with you completely that people should watch out and be vigilant as there are many people who are Gambling addict's and don't even know about it and is moving about without having foreknowledge of it as most of the signs listen here are visible in most people
One of the sign that is common among gamblers is financial instability due to the high habit of Gambling it will be very hard for those involved Gambling to save money because they are always thinking of how they will satisfy there Gambling emotion so any little money that comes to their hands will be used to fulfill their desires that is why most gamblers are always in depth
Thought, I would like to comment on the gambling signs of addiction and financial problems. In reality, it would be possible for one to find a person who is addicted to gambling and it is still in a relatively early phase of their addiction,.so it is possible for them to suffer from addiction and yet not to have depleted their financial resources.
Financial doom and despair are usually signs of gambling addiction which already has developed through months or years and it has become crippling, the efforts for any responsible gambler must be to never reach that point in their gambling journey.
It is a sign, but a late sign of addiction, we should be rather interested on things we can catch early before losing all our capital to our bad luck.