There are a TON of apps/programs that offer some sort of “free” content that we download on our computer and phones. With that “free” content, you may be getting more than you initially thought. You may also be downloading viruses & malware. Amazon Fire TV & Fire Stick are now also at risk of downloading content that could infect other Android decics that are connected as well.
If you are using the Fire TV & Stick, in accordance with the manufacture’s instructions, you are more than likely not impacted. However, if you are starting to dabble in “watch for free” apps, you may want to run a virus scan of your network.