Withhold from deposit for insufficient notice to vacate?

[Sarah D.]

Can't decide if this is a good business decision or a petty decision.

• Tenants provided 17 day notice to vacate
• Tenants were advised that they are in violation of the lease by not providing 30 days notice.  
• Tenants come back with sob story about how short notice is due to upcoming deployment (they are moving across town, wife is staying here during deployment, no military documentation provided)
• Move out date is accepted; if they want out that bad I don't want to force them to stay for fear of damages

By CA law we can withhold 13 days of rent from their deposit due to insufficient notice to vacate.  From the CA court website:

"If you pay rent once a month, you have to give your landlord 30 days’ notice in writing. If you do not, the landlord can charge you for the unpaid rent even after you move out. Unless a new tenant pays the rent, you will have to pay for those 30 days. If you pay rent every week, you have to give 7 days’ notice."

So my question is, would you withhold the 13 days rent?