Hi Carol--late to this thread, but I've been a RL dealer for several years.
I've always admired RL's determination to maintain high standards, and, in the vintage clothing offerings, to really try to keep non-vintage stuff off the site. But...
Your policy as stated really has some elements that strike me as incredibly wrongheaded...
If you insist that something originally sold with a paper tag still be sold with that tag, you are essentially requiring vintage clothing to either be labelled or deadstock. That puts unrealistic constraints on your sellers (vintage labels are quaint, often quirky, and fun in and of themselves, and deadstock is great to find, but both are only a fraction of what's out there). And it also drastically curtails the shopping opportunities for RL customers, who will have to go elsewhere to find the full range of wonderful vintage clothing available to them at this point in time--just as they have to go elsewhere for their vintage swimsuits... ';)
If you insist that only labelled or hangtagged post 1945 clothing can be proved authentically vintage, despite the ability of every dealer in the VFG to point out telltale characteristics of construction, style, etc that help to date vintage clothing--even without the benefit of consulting the hundreds of label examples in the VFG Label Resource--then why don't you impose the same constraints on post 1945 costume jewelry, which often does not bear a manufacturer mark and must be IDed/dated through dealer expertise rather than through what's been stamped on a cartouche? (Also, to extend the analogy, just as labels originally present on vintage clothing detach or fade, so too manufacturer imprints on vintage costume jewelry can become so worn they're just about illegible--but that doesn't make them unlistable on RL's jewelry lane).
How does one distinguish a vintage 50s rhinestone pin from a contemporary Made in China piece of junk, without benefit of a maker's mark to guide them? Well, even though a buyer unfamiliar with vintage jewelry may be stumped, it's not really a very tough call at all for an experienced dealer. And you seem to accept that fact in your vintage jewelry listing policy. In fact, you even have an article detailing how to correctly ID Delizza & Elster jewelry--which was originally sold only with a hangtag. Why not announce that D & E jewelry can't be sold on RL unless it retains the original hangtag? Well... because there's a ton of gorgeous D & E jewelry out there, almost none of it with the original hangtag, and you know that you would only be hurting your sellers, your customers, and your site by needlessly restricting its sale.
Same thing here. You're not protecting customers, you're depriving them, ensuring that they'll have to shop elsewhere. And you're irritating and alienating some of your most knowledgable, experienced, and ethical vintage clothing dealers as well, so that they feel they must sell elsewhere. Why on earth would you want to do that?
I really hope you'll find a way to incorporate the ton of excellent advice/feedback/info you have gotten from VFG members on this thread into your policy, before RL is irreparably hurt...