Working at companies that issued laptops and phones, people looked at me sideways when I told them that I in fact carried two laptops and two phones.
It's not just for photographs taken south of the border, so to speak.
If you do anything on company property or time (including laptops and phones) that isn't 100% company work, it can get caught up in subpoenas, discovery and other miscellaneous legal proceedings that your employer may be a party to. This can land you in legal hot water even if these activities had nothing to do with your employer. Once the DA's got your files, they can charge you with anything you may have dug up even if it's not related to their primary inquiries. Your drug-fueled trips to burning man may not look so entertaining to the DA.
Further the California blanket IP ownership exemptions only apply to things you do on your own time and your own property. If you come up with a fun startup idea, and you write some notes down on your work laptop or text your buddy on your work phone, you should just assume it belongs to the company.
Anyways, for anyone who needs to hear it again, for the love of all that's good and holy do not take photos of your genitals with company property.
And if you work somewhere you're assigned a laptop and a phone, you can probably afford your own of each. If that's the case I highly recommend it. As an Apple employee, the corporate discounts are worth taking advantage of.