Thank you for asking. [sg-lux]
Short answer is:
#No, you don't. And I will exploit this until it's fixed.
Long answer:
I have done it countless times, and even though it's seen as trolling or AFK; it's not if you go onto a laner other than your ADC. Why? Because then your ADC takes solo experience. Many times, I've recalled and hopped onto my mid / toplaner. And then what? I go prepare a cup of tea.
Usually I go to start getting the water boiling and come back to check. If they're low I use both my heals and the heal summoner, then go pick which tea I'm feeling for this match. You can only do this in early game otherwise someone will know something's off, but if you're in low-elo you can just hop on the hypercarry and watch Lilypichu / Dark Mane the whole time.