The Stack Exchange engine has a pretty simple little filter to see if the title of a new question being entered is subjective.
Apparently it usually looks for any of these keywords:
And if it finds any will throw up this warning:
The question you're asking appears subjective and is likely to be closed
It's not perfect, some people notice it, others don't, there will always be somebody asking subjective questions. But it's still not a bad idea. However here on travel.SE there's one more very common keyword in subjective questions. Could we please get it added to the list just on our site:
For instance, here's some titles that don't look objective without going on to read the full question:
Is the London Pass worth the price? • Is it worth booking Amtrak in advance? • Is Mount Pilatus worth visiting in winter? • Is Anjuna beach worth visiting in Goa? [closed] • Are cruises' Shore Excursions worth the money? • Is it worth leaving the hotel in Verona on January 1st? • Places worth visiting by train from Munich to Berlin • Which chateaux of the Loire are worth visiting? • Which of the many Stepwells in India are worth a visit? • Is it worth it to go to Mount Kenya for only one day? • Is the Pilanesberg safari park worth to be a primary travel goal?