I can't count the number of times I've lost cannon minions before I had the chance to last-hit them because my ADC didn't realize that I had a charge of 
and last-hit them instead of letting me do so.
So, can we have an "I have Relic Shield" ping? It might not seem worth it to have a ping specifically for just one item, but I really think it could come in handy.
Just ping on top of the cannon that you're "On the way"
Maybe a visible aura or an overhead notice.
It would be nice if Relic Shield and Targon's Brace had an active that lets you attach a tiny icon with an arrow pointing to a minion. ######Yeah yeah, Clarity, but it'd be really small and doesn't even need a sound cue.
Work with ADCs that actually watch what the hell is going on. ;)
Seriously though, when I'm support I ping cannon minions if I have a charge or an imminent charge. Many ADCs I've played with ping the cannon minions when they see I have a charge.
