Does the word" i agree" in the safe search really safe?

in searching for anything in the net, most often times we are being warned safe search off, then click "i agree", if the subject is for mature only. does it really that safe ? does the system really sure if the user is adult or a kid? or i think its time now to look for this matter, microsoft has a lot of work for this one, maybe, kids now adays are more technology wiser,and curiosity is where everything started to develop, creativity are bonded with responsibility, mind is the core of bodily mechanism and reflexes, anything that visually captured are absurbed in the mind , and kids are not that strong to control their sense and emotion.. in this sense i would say, its too hostile for the kids to be expose in the net alone, " to save life, secure the mind and the body will be healthy", there"s too much business out there in the net and everyhting goes, " i agree" is the magic word of genie in the bottle to provide you from total holliness to extreme wickedness , and domesday begins