Yep, go with your gut on this, but I'd never change jars for a client...labels or lids, yes. I own antique stores that we rent space in, I can tell you from personal experience that 70% or more of the people we rent to are a bit flaky. That being said, sometimes getting into a store that rents space is contingent on having pictures of your products to show the owner, so she may be trying to come up with a line for her booth. I'm very picky about who I let rent now that I've learned the hard way and I require pictures.