Encoded HTML on legitimate email?

I’ve gotten a couple false positives in the last month due to the “Encoded HTML is always spam” heuristic. The messages appear to be coming from legitimate businesses that I probably did business with in the past, although they’re definitely coming from a bulk emailer program. (The messages were for new product announcements.)

Assuming that these are legitimate commercial emailings, does that mean there’s some legitimate reason for the bulk emailer to use encoded HTML?

I’m not aware of such a reason (it makes the message larger and obscures its contents) but if you do get legitimate messages that are encoded HTML, you could turn off Encoded HTML mail is spam in SpamSieve’s preferences.