Keep in mind that there may be mitigating circumstances that you (ie your character) may not know about.
With that said, Danger Sense is a passive ability - you do not need to concentrate or activate it - and it *IS* worth 150 CDP!!! When you’re building a 500 CDP character, that’s a pretty major ability!
This is very different from Danger Sense abilities in other games, where the character is only aware of attacks directed specifically at the character - indirect attacks from falling debris and such do not trigger the ability. If your GM has played a lot of other RPGs, he may be confusing the ability between game systems.
Without being adversarial, try speaking with your GM outside of the game (never debate or call out your GM on rules during a gaming session!) and ask him what he believes the ability is for and how it works. Present him with examples and ask whether or not he feels your character would warrant foreknowledge. Lastly, point out the CDP cost in relation to your total starting CDP as I did above. If after discussion, you feel that the ability is not worth the point cost, see if your GM will allow you to lower the point cost to something you are both happy with, ie maybe only 50 points if you have to be “heightening your senses” in order for it to work, or if it only works against attacks that are specifically targetted against you.
Or, get rid of the ability all together and put your points somewhere else. Barring that, have your character dive on the proverbial grenade next gaming session and have a new character ready - one that is surprisingly very close to your current character, but without the ability.