Sellers who use “unlimited revisions” as a promo slogan in the hope of attracting buyers who choose them over sellers who don’t offer unlimited revisions, have to keep in mind that they then also bear the risk of buyers actually making use of those unlimited revisions which are part of the gig the buyer buys and pays for.
If you think your unlimited revisions is the best value proposition you have to offer and it’s (just) 1 in (100) buyers or whatever your stats are, you could choose to regard the time you’ll spend on those revisions as a kind of promotion fee you’re paying to use the “unlimited revisions” lure, to make it psychologically less painful.
If it’s too many buyers to write it off as cost of doing business, or not many but it takes you far too much time, you better get rid of the “unlimited revisions” and think of a better value proposition, like a quality that won’t need unlimited revisions.
However, if the revisions are due to mistakes you made, I guess support would side with the buyer even if you only included, e.g., 3 revisions in your gig, when the buyer still finds mistakes you made after the 3rd revision. If buyers ask for unreasonable revisions (more than the 3 you included, revisions due to their own mistakes/negligence, revisions that aren’t revisions but asking for new work, etc.), you can decide on case-by-case basis if you want to just do the revision (there are scenarios where it might make sense), or send a gig extra to cover the additional time.
Buyers who take you up on what you promised, unlimited revisions, in this case, may or may not be unreasonable with their wishes for revisions but they aren’t fake buyers.
A fake buyer would be someone who’d buy your service without even the intention to get your service, like, for example, a competitor, who’d buy and not even download the delivery, or not intends to use it, in any case, but just buys in order to leave you a bad review.
I agree with anyone who says, don’t put anything like “unlimited”, “100%”, “(satisfaction/money back/…) guarantee”, etc. - don’t put anything you are not able to or might not be willing to deliver.
Unlimited is unlimited, 100% is 100%, guarantee is guarantee.
Words have meanings, and people can hold you to those words, or ask support to hold you to those words, if you don’t honour them.