Perhaps I have missed something as all the streaming services I have are for my personal use - but can't they just limit the number of concurrent connections fr

Perhaps I have missed something as all the streaming services I have are for my personal use - but can't they just limit the number of concurrent connections from a given account? It'd be pretty lame if you had to check if your friend wanted to watch something before using Netflix and that'd probably drive anyone who was actually a lost sale (rather than someone who will never pay in any case) to purchase their own account. I realise there are family deals etc. but that's a risk the companies take in creating those deals (that they will make more money than they will lose).