Lawn mower blade

My friend went to the big blue to get a new blade for her lawn mower,
she looks through all the blades that they got to offer and found found
the one that she needed and asked the clerk installation.she spends 15 min,s
for this guy to explain to her about trailing edges and how install it,she gets
it home un packs the blade and stamped in the blade(THIS SIDE UP)

The miltary had to put "Front toward Enamy" on the claymores.

When I worked on jets many years ago...
They had a variety of safety devices that were put on the planes when they were parked...

Ejection seat pins, Engine intake covers, pitot covers, probe covers, landing gear locks, etc...

They all had red streamers attached that said "Remove Before Flight"