If you were normal… 20/4/19xx … or 20th of April, 19xx. If you insist on freedom units and format, its your own fault!
Also, who knows what it was written to identify? you are all speculating. It could have been weed smokers (420) but it could also have been written to filter out the yanks…!
For tipping countries like the US, the driver would only get a “has a tip” notification on the order (if they get any information like that at all!) so they can decide. There is no way the driver can see that there is a $40 order with a $4 tip, or a $40 order with a $16 dollar tip. Orders would be ignored all the time, and the service would fail.
Oh, and if they did get a “has tip” flag for the order, then customers could just game it, by selecting “add tip” and setting it to $0 or $0.10 or something so their order gets that “has tip” flag!!
Here is AU, there is no tipping, so the drivers get paid like normal people. None of this work for tip bullshit that seems to have survived this long in the US, its incredible that it has gotten this far. Now the US get asked for tips using self-service machines, that is the height of lunacy!