Some situations do not require inspecting anything, because the context alone is the verdict.
Glass-top boxes: Habanos does not produce glass-top boxes. The classic tourist fake — 25 or 50 'Cohibas' under a glass lid, often with a certificate — is fake every single time, no exceptions.
The price is the tell. Genuine Cohiba Esplendidos cost serious money everywhere on earth; a box for $100 from a beach vendor is not a deal, it is a prop. Counterfeiters price fakes at 'plausible bargain' levels precisely to trigger deal instinct. Related: anyone claiming their cousin works at the factory and gets them out the back door. That story staffs half the counterfeit trade in Havana.
Wrong sales channel: real Habanos move through licensed tobacconists and the La Casa del Habano network. Street vendors, beach hawkers, taxi drivers, market stalls, and websites offering to ship to the US are all, at best, gray-market — and overwhelmingly fake in practice. In Cuba itself, buy only from official stores; in Mexico and the Caribbean, from licensed shops.
Are the Cuban cigars sold in Mexico real?
In licensed tobacconists and La Casa del Habano stores, yes — Mexico is a legitimate Habanos market. From beach vendors, flea markets, and 'special deal' resort sellers, overwhelmingly no. Same country, entirely different odds depending on the counter you are standing at.
Are fake Cuban cigars dangerous to smoke?
They can be genuinely nasty. Counterfeits have been found containing floor sweepings, stems, non-tobacco leaf, and material processed without any quality control. Most will just taste harsh and burn badly, but you are smoking an unregulated mystery product. The money is the smaller loss.