It’s cryptocurrency, the responsibility of knowledge lies with the user.
Perhaps for fiat back currencies, it’s not a bad idea, but does that give to much false hope if the fiat gateways aren’t subjected to an agreed upon 3rd party audits.
Proxy tokens issued by crypto gateways would be good to be verified, but still flawed. The better solution would be eliminate gateways in favour of a smart contract ecosystem verified by PoS and the full nodes for issuing crypto proxy tokens backed by the actual crypto token. See my brief outline here, https://forum.wavesplatform.com/t/how-are-crypto-gateways-secured-and-what-would-happen-if-they-are-hacked/1860/6. These should be marked as such.
So maybe rather than a boolean for verified, it needs a voting mechanism to tag tokens, eg, Spam, Fiat Backed, Scam, Gateway Crypto Backed, etc.