I think this is way too far. For me personally, the threshold to put the logo is someone within the company is paying, even though the whole company is not in a contract. For example, you might not have a full fledged contract with Google, but one manager of a tiny team might have used her/his company credit card to pay for your tool. If the sum is below a certain threshold, they don't need to authorize or go through vendor vetting and all that.

The threshold should be that a relevant representative of the company agreed to have the logo displayed on the website. Anything other than that is deceptive.

Well "Joe in accounting from Google is using it" doesn't have the same glamour as putting the Google logo apparently.