For most people, compliance is a background issue. You're not going to get in trouble for buying a 70/30 VG/PG blend. But there are two practical reasons to care. First, buying from a compliant retailer means the product is less likely to be counterfeit or mislabeled. That protects you from getting a stronger nicotine dose than you expected. Second, if you travel with e-liquid, you need to know that TSA rules apply to all liquids, regardless of VG/PG. We've covered that in Flying With a Vape: TSA, Cabin Rules, and the International Pitfalls, but the short version is: keep it in your carry-on, in a quart-sized bag, and check the rules for your destination.

If you're a retailer or a distributor, this gets more serious. You could face fines if you sell products that don't meet FDA labeling requirements. But for a consumer, the checklist is simple: check the label, verify the retailer, and know your local laws.