That's not the case actually.
Using a GET variable means you are calling your server action with url parameters, which means your users can run it directly like:
in their browser. And if it happens that you have not secured it well they can delete any record just like that.
When using a POST variable, the data is submitted by a form and you cannot just run the url with a parameter added there, the server action can only be run on form submit.
That's why the default value points to a POST variable, but i see no issue with that ... if you want to use GET variables, just pick them in the data picker.
Yes, security is very important… I see what you are saying.
All my deletion server actions have security protects… so would you say that they are completely safe from outside interference as you described in your post?
that is true… but it takes someone who is still climbing towards the summit of their learning curve a short while to work out why their server action isn’t working.