If you want to register to a store it is a legal requirement in most countries that you have to click the "agreed".
We use the joomla user registration and therefore the "agreed" is mandatory.
If someone fills the "agreed" for the registration, the TOS is automatically checked. So you should think twice if you just want to remove it.
So, but how to solve your problem if you insist to remove it. There are various methods.
Just set the default = 1.The only disadvantage is that your users still can see it, but you can set it to hidden and that it is not displayed.
In VirtueMart 3 there are two userfields, one for the registration "agreed" which is mapped to the joomla agreed and a real TOS field, which is only for the TOS.
If this does not work, for whatever reason. Then just remove it from the layout and add a hidden field with value =1 and name tos.