If you embed videos the usual way, youtube sets extra cookies in your users browsers. If you do not want this you need to embed itin a custom way with a custom link

<object style="
   width:650px;
   height:365px;
   position:relative;
   display:block; 
   max-width:100%;
   margin: 0 auto;" 
      type="text/html" 
      data="https://www.youtube-nocookie.com/embed/QRObu4nYS2g">
</object>

output: