Do you need to play Deflect cost for Akshan to steal a Hexdrinker equipped to a unit?

No, you do not need to pay the Deflect cost to have Akshan steal a Hexdrinker that is currently attached to an enemy unit.

Ruling

When you target an attached piece of equipment with an ability (such as Akshan's trigger), you are targeting the equipment card itself, not the unit it is attached to.

According to RiftJudge FAQ 734:

• Equipment cards have their own properties, distinct from the unit they are attached to.
• While Hexdrinker's Deflect keyword is in its Effect box and becomes active when attached to a unit, that Deflect effect is granted to the unit, not the equipment card itself.
• Because the equipment card does not possess the Deflect ability as its own property while attached, targeting the equipment does not trigger the Deflect cost.

Sequence

1. Akshan's Trigger: You play Akshan and trigger his ability to steal an enemy gear.
2. Targeting: You choose the attached Hexdrinker as the target.
3. Cost Check: Because the Hexdrinker is currently attached, its Deflect effect is being applied to the unit it is attached to, not the Hexdrinker card itself. Therefore, the Deflect cost is not applicable to the Hexdrinker card.
4. Resolution: The Hexdrinker is successfully targeted, detaches from the enemy unit, and attaches to Akshan (as per Akshan's card text and RiftJudge FAQ 657).