Terms of service checkbox (agreement) for specific products
 

Hello,

I would like to add a "I understand this and that" checkbox to X Cart 5. In a way, it would be a bit similar to the one discussed in this thread (x cart 4)

If possible, I would like this checkbox to be mandatory only for specific products (I have added an * to those products' names but I'm open for any other way to differentiate them)

I've thought of two ways to implement this :
1. Prevent users from adding those specific products in the cart, by disabling or hiding the add-to-cart button with JS code unless they check the checkbox (which would be an attribute Yes/No field, to prevent users from buying without going through the product details page)

2. Prevent users from completing checkout, by disabling or hiding the Place Order button with JS code unless they check the checkbox (which would either be right in the checkout page, or in the Terms of Service popup).

Could anyone help me with this?

Thanks a lot,