Never experienced this sort of problem. For instance, I was in Ulta tonight for probably an hour with my girlfriend testing many different fragrances. I even had a pen to initial the test strips so I could remember what I liked afterward, too. And even from the onset coming into the store, I received one greeting and asked if I needed any assistance and I said, "No, thank you. I'm just looking." Afterwards, I didn't feel as if any of the store associates were growing tired of my semi-long stay, either - no lingering or "the look" from SAs.
In the end, I spent over two hundred dollars on fragrances in their store so I'm sure they sensed then that I was giving serioius consideration to the scents rather than merely being there to waste time. Moreover, a month beforehand I had been in Ulta for nearly half an hour and didn't make a purchase but sampled five or so fragrances and didn't get any unpleasant feelings from the SAs when I had left without buying anything.