That’s so wrong, messing with someone’s livelihood! And without asking or offering reimbursement of some sort!!

Off the top of my head, I would suggest your friend stick the offender with a bill for whatever the goods cost, cleaning expenses, and anything else attached to the incident. If she was unable to tend to her client and lost the appointment or anything like that, then the bill should include the fee she lost, too!

Well. Since no one person is all angel, one devil, I’d say in some way she encouraged (without really knowing or thinking about it) the encroachment on her boundaries. Maybe this person was a new hire and foggy on procedures? Maybe this person was a new hire, someone your friend had been really friendly to, who concluded ‘so and so won’t mind’? Why don’t they have separate lockers? It’s best to approach as a learning experience, where she’ll assert herself and learn to speak her mind / feelings.

When I was younger I had ppl encroach on my boundaries all the time – especially lately that’s stopped. Generally ppl are just clueless when it comes to interacting with Pisces / 12th house.

Boy, that takes some ‘balls’! I know confrontation is difficult, but, try to assume the person was REALLY in a jam or they wouldn’t have done this (this gets you in a less confrontational mode)…Say, “I’m sure you must have been in a big jam or you wouldn’t have used my stuff. I am wondereing when were you planning to reimburse me for the $50 ( or whatever the cost) for the materials.” Then, telling them you know they MUST have been in a jam, but, you really prefer they leave all your things alone in the future.

Everyone’s focused on the cost here, but I’m wondering if that’s what your friend is most interested in. Personally, I was be more cheesed about the intrusion into “my domain.” (i.e. Don’t use my stuff without asking, regardless of whether I pay for it myself!)
In any case, as much as your friend dreads it, a “confrontation” will have to occur. Even if it’s as mild as, “Hey, the other day you used my stuff and didn’t clean up after yourself. That [made me late/cost me my client/whatever] and I would appreciate it if you would ask next time.” The offender will only continue to misbehave unless the point is made that this is unacceptable.
Of course, you can scale it up to your preferred level of drama.

You’ve made me curious, so now I’m going to ask my hairdresser friend how she’d handle it.

I’m a Pisces Sun(also Mercury and Venus in Pisces), and this type of thing has happened all the time to me, too. I shirk from confrontation, but I think SaDiablo’s mild approach would probably be the way for your friend to approach the situation, IMHO.