The way you handle your seedphrase will determine if any other person can have access to your wallet or not. You are the one who can secure your wallet proper if only you can store your seedphrase in a place where no eyes can find it. If you are using a good wallet you don't need to be scared if your wallet will be hacked just like that, someone else can only get access to your wallet if only seedphrase is stored in a way that can be exposed. 

Some people stored their seedphrase in online handle or messages that are easily hacked, when this is done the hacker can get information of you to steal more of your valuable asset. It is better for you to know where is best to save your seedphrase that you alone can have access to it anytime.