Retailers have long used fragrances to affect the customer in-store experience. See for example Air/Aroma.
So perhaps we can use smell to alert consumers to dodgy websites? An artist and graphic designer, Leanne Wijnsma, has built what is basically an air-defreshener: a hexagonal resin block with a perfume reservoir inside, which connects over Wi-Fi to your computer. When it notices a possible data leak (like the user connecting to an unsecured Wi-Fi network, or browsing a webpage over an unsecure connection) — puff! It releases the smell of data.
James Vincent, What does a data leak smell like? This little device lets you find out (Verge, 31 Aug 2017)
That's all very well, but it only sniffs out the most obvious risks. If you want to smell the actual data leak, you'd need a device that released a data leak fragrance when (or perhaps I should say whenever) your employer or favourite online retailer is hacked. Or maybe a device that sniffed around a corporate website looking for vulnerabilities ...
I'm sure my regular readers don't need me to spell out the flaws in that idea.
Pax Technica - On Risk and Security (November 2017)
UK Retail Data Breaches (December 2017)