As well as mid-career engineers who don't have a time nor willingness to prepare for CS-riddle based interviews.
Spent the time hanging out with my girlfriend instead. Worth every minute.
Why? First, you never know. Maybe they legitimately want your skillset - why fake up some crap you hate for a job you don't need? Second, you'll get practice taking interviews in a very low pressure situation. Worst-case they laugh at you and you fly home. Best-case you get an unexpected job offer you can evaluate. Either way you got some practice and "game time" with the process so if you're ever in a more high pressure situation (e.g. you really need the job) it's a lot easier.
Plus, smart people meeting other smart people is never a bad thing.
Having done this when I was younger and more foolish, I would not recommend it at all. I felt like I did pretty well overall, but ultimately flubbed a couple of [simple] questions that torpedoed my chances. While things worked out for the best (that company's future looks grim and I'm very happy where I am now), it was a blow to my confidence at the time.
I probably wouldn't have had to have prepared for a month or two to get that offer. A week of glancing at my notes for 30 minutes to an hour a day to refresh would have been sufficient. I think you owe it to yourself and the company who is paying to fly you out to at least brush up a _little_ bit (within reason) beforehand. It's almost like basic hygiene.
Companies keep records of their applicants and interview feedback. I'm dramatically oversimplifying, but your feedback will spell out two things in isolation: your fit for the role you applied for, and your fit for the company in general. If you do badly enough not to clear that second hurdle, you're going to have a hard time getting future interviews at the company.
So I wouldn't recommend winging it in a Big 5 interview unless you're comfortable with the possibility that a bad performance might blackball you there. But hey, some folks are fine with that risk. Others are confident enough that they feel their seat-of-the-pants performance will still clear the basic hurdles. If that's you, then more power to you.
After going through "interview training" for one, they do blacklist people. But it's probably not as bad as you think. Also, even after getting pushed out of one org, another was extremely happy to offer me a job years later despite having all the info on me (even if I turned it down).
Individual hiring managers can have a good amount of discretion.
The cost of the flight & hotel is pretty trivial in the grand scheme of things. By that I mean relative to stuff like going to a place you want to see, the value of spending a vacation day, etc...
I do agree that the meeting smart people is fun... but the full on crash-and-burn on an algorithm + whiteboard interview would really have a massive negative impact on my confidence & self-esteem. Not worth it.
This is a fair point, but I simply want to point out that was half the reason I suggested it. Learning how to fail :)
I very much understand the mental aspect here though, so that's a tough one and my advice is not for everyone. I will say that at some point in your career you will fail though - or you aren't pushing yourself very hard. I believe this was one of the harder things I had to "train" myself to deal with; the mental load of failing at something and how to recover.
If you're not in a mental space to make that experience a positive for you? Absolutely skip it.
It's really worth it, IMO. There's really a HUGE element of luck: from the personality and opinions of those interviewing you to the questions they happen to choose that day. Seriously - internalize that and just try it out!
On the flip side, it takes a huge amount of forethought to create different tests, projects, and screening practices for every position and then re-shaping for each experience level, particularly if the team is young and inexperienced; it's difficult to test for what you don't have yet.
I'm never doing another hour-long whiteboard interview again in my life however. The whole process has become so gamified now that most new entrants have practiced the exact types of questions asked hundreds of times. I'm not interesting in spending a month of my life doing that any more and I no longer need to.
The whole SAT-prep feel of the interview process now is tiresome.