I think you're saying some or all of these could be what Joel and Jeff refer to as "meta tags".
I guess I can see how sightseeing, seasonal and activities could be thought of as a bit meta.
Sure there are no experts in sightseeing for the whole world, but there are experts for sightseeing in particular places. And there are definitely people who are experts in some places but don't do much sightseeing, like myself (-: And the other word Jeff and Joel use is "characterise" when they talk about good tags. I do think lots of questions are characterised by being about sightseeing. The sightseeing tag also has a bunch of synonyms which might be a hint that it's useful.
Seasonal is harder to think of any kind of expert for but it definitely characterises questions.
Activities is meta in just the same was as sightseeing I think, it really only makes sense in combination with a place. But these questions are always used in combination with a place and they are always questions about activities so I also think it characterises questions.
As for "vantage points" and "event travel" these really do characterise the questions they're used with. For the former there's really no other characteristic tags other than the locations. For "event travel" I think there actually are experts - but not on all events. But the questions are not numerous enough to split it up into say "concerts" and "soccer" where it's more likely that the same person would be expert across everything the tag covered. I think it's fine to have a broad tag which has experts for various of its aspects and for only various locations.
Events might work better and better with more synonyms. So a football expert might want to watch football and end up watching events for instance.
But I'm interested to hear from others too since I agree it's tricky and murky and quite possibly different to the tagging problems of Stack Overflow et al.