I’m on kbin too and I can see the alt text in the raw HTML:
<img src=“https://kbin.social/media/cache/resolve/post\_thumb/51/85/51859cfc559d9aedfa1bec8e33bbb76fd6c3c6d8b8eaf0ee854a68164df83780.jpg” alt=“A machine displaying 108.6 onions per minute. The image is captioned "Tony Abbott’s Mouth".”>
However, my browser isn’t showing me the alt text in the tooltip.
I think the service charge bit, that is widespread as an alternative to tipping in Europe, makes a lot of sense in general.
Key word in the above sentence is: alternative