Roaming supports - XP for placing and/or destroying wards?

Vision/denial can win games but supports seem to end up under leveled, together with the lesser gold income that comes with the role. Getting some additional XP would benefit roaming supports and enable them to catch up some of the experience they miss while not being in lane. To not let it be abused by other roles it could be tied to a support mastery?

Would love to hear more thoughts about this suggestion, especially from higher elo support players. How do you manage to balance roaming and keeping up to level?