It seems like the loading behaviour is not chosen by the sites, per se. The options (lazyload or eager) are documented as being 'recommendations' to the browser

It seems like the loading behaviour is not chosen by the sites, per se. The options (lazyload or eager) are documented as being 'recommendations' to the browser. The default setting is "auto" which means it's up to the browser. So theoretically the browser could still give the user a setting.