It doesn’t sound like the are.
First, this woman is a great example to use. When she sits there all day, she’s claiming to be successful, but spends all day in the spa doing nothing but waiting. Do others want to do that? Is that what a successful person does?
I used to do market surveys. Some stores got ticked off because I’d go in with a clipboard and record prices, but (at least in VA) the point was that they were inviting the public into their store and couldn’t invite just some of the public. I heard about that coming to a court case somewhere. A chain store found the manager of a competing small store in one section, writing down prices and kicked him out. I don’t know how many times that happened, but he sued to be allowed in and won. Half an hour after the court case ended, he was back in there, with his clipboard, writing down their prices.
I would think they could post “No soliciting” notices and make it clear that their policy prohibits soliciting their customers to sell products or services or memberships or business opportunities. They can include that wording in a smaller lettering on the sign. If they’re part of a mall or strip mall that has any security people, they can find out if they can escort a person off their premises for violating store policy.
If so, then they should have the rent-a-cops escort her out. She may make a scene, but if she’s escorted out every time she shows up, she’ll give up sooner or later. If she does make a scene or refuse to be escorted, she’s doing herself in because that’s the perfect chance to call the police. Especially if she causes a disturbance.
If they aren’t in a location with rent-a-cops, they can rent their own. Call a local agency, preferably one that uses off-duty officers. I’m guessing they’d cost more, but that way they’re getting someone who should know the law. Work out a deal to hire them for a week. Let the woman in. After all, she might be a customer. The first time she approaches someone, he can point out the “No Soliciting” sign and ask her to stop.
They can also check with the police and ask if they can have the police remove a person in the store who is violating their store policies.
There are some more, slightly subversive tactics they can do. They could set up a security camera, which could be any kind of camcorder set up in a hidden location. Tape can be expensive, so what I’ve done is connect the camcorder output to a regular VCR, put in a extra length tape (some do 8 hours in the slow mode), and record on the VCR tape instead of the camcorder tape. Or you can use shorter tapes for better quality, since VCR tapes are cheap and it’ll be easier to get to the VCR to change a tape than to a hidden camcorder.