Enforcement against tenants

The bill goes to you, the owner

Your governing documents don't care who was actually walking the dog off leash or parking in the fire lane. The association's enforcement relationship is with you, the owner of record, whether you live in the unit or rent it out. A violation notice, a hearing, and a fine all get addressed to your account, even when your tenant is the one who broke the rule.

"As a property owner within an HOA, you are the party ultimately responsible to the association, regardless of whether you occupy the property or rent it out."

Source: Landlord Lifeline: Navigating Tenant and Neighbor Disputes in Your HOA Community, Manning & Meyers

That responsibility doesn't disappear because a lease exists. It's your CC&Rs the association is enforcing, and your account the fine lands on.

Your tenant and the hearing

If the association schedules a hearing over your tenant's violation, the notice goes to you. Your tenant doesn't automatically get a seat at that table.

"Fines levied for rule violations committed by your tenant will typically be assessed against your account... your tenant generally does not have the right to attend this hearing unless you authorize them to accompany you."

Source: Landlord Lifeline: Navigating Tenant and Neighbor Disputes in Your HOA Community, Manning & Meyers

You can bring your tenant along if you choose, useful when they know the facts better than you do, but the hearing is still yours to attend and respond to. Skipping it because "it was the tenant's fault" does not change whose name is on the notice.

Enforce it the same way, occupied or not

A board that goes easy on violations in owner-occupied units but comes down hard the moment a unit is a rental is building a consistency problem, not just an unfairness one.

"The governing board or its appointed hearing panel should ensure that all violations of rules and regulations of which the association becomes aware are enforced in a consistent, uniform manner using common sense."

Source: Rules Development and Enforcement, Community Associations Institute

Treat a rented unit's violation exactly the way you'd treat the same violation next door. Anything else hands the next owner a defense to raise, covered in Owner defenses.

Can you bill your tenant for the fine?

Once a fine is paid, whether you can recover any of it from your tenant is between you and them. It depends on what your lease says about association rules and who bears the cost of violating them, not on anything the association enforces directly. Check your own lease and your state's landlord-tenant law before assuming you can pass a fine through.