They are blinded
the leprechaun disipires
They start screaming at you in Irish and their face turns red.
Because you see Unicorns omnomnom on grass so they can see the green leprechauns running in between. Leprechauns are very sneaky and like to annoy unicorns.
Tradition says leprechauns can't see green. So you pinch someone to warn them leprechauns can see them. You pinch them for their own safty.
If you see a leprechaun's footprints, you probably would want to follow them to see if there really is a pot of gold at the end. If that fails, follow the leprechaun's footprints to the leprechaun itself, and catch the leprechaun in a net to sell it for research.
Leetle tinyy leprechauns
There is no such thing as a leprechaun which makes them very difficult to see.
Leprechauns have magic, but leprechauns aren't real (As far as we know...)
Leprechauns are fictional characters.
There are no leprechauns except in stories.
No. Leprechauns do not exist.
There are no such things as leprechauns.