A trigger warning on this post for Android devs would’ve been nice.

From StackOverflow:

Switches will send packets to all interfaces when using broadcasts or under extreme conditions (full MAC Address Table). This can lead to duplication if there is a loop between two or more switches and if the Spanning Tree Protocol is not used. So the answer is rarely.

https://stackoverflow.com/questions/9196791/duplicate-udp-packets-how-often-it-happens#9220574

The cost effectiveness difference on the bottles versus sponges is probably much bigger than the video suggests, because a whole bunch of ink is likely sticking to the sponge and never coming out.