Is it correct to say "The development team are seeing a new trend", when you're certain that the team consists of several members? Or, is the word team strictly singular in any context?
According to a variety of references, you may use is and are depending on the context. Here is an excerpt from Grammar Girl's appropriately named Quick & Dirty Tips:
Let’s use the collective noun “couple” as an example. When you are thinking of the couple as two separate people doing separate things, you would probably use a plural verb. For example, you would say, "The couple are vacationing separately this year," because they are two different people doing two different things. On the other hand, if you're thinking of the couple as a single unit, you would probably use a singular verb. For example, you would say, "Each couple is going to Bermuda on a different day." You just have to use your best judgment, and even though this seems tricky, the good news is that you can never really get it wrong because 1) there is no real rule, and 2) you can always just assert that you were thinking of the couple as individuals (or a unit) if someone questions your verb choice (2).