Honestly speaking I see it as both, but mostly I see it as being a nuisance. These days, a lot of places have been increasing security levels in response to the large amounts of things like terror attacks that have been happening, especially really popular tourist destinations. I think the threat to security would be bigger in places and countries where security protocol isn’t as rigid as it is here in the United States. Of course, the increased security doesn’t mean that some bad people can’t slip through the cracks, and even if there aren’t bad people who make it through, large crowds pose a danger both to locals and the tourists. But I still think the large groups are more of a nuisance, getting in the way of everyday life, possibly being rude and acting as if they are entitled to everything simply because they are in vacation, as generally just disturbing the flow of traffic, not just road traffic, but public transportation, walking places, or even stores. Overall, for me, it comes down to my lack of patience with people, particularly when there is a large crowd of them.
Tourism Around The World Blog 