That was true a year ago, I don't think it's true today. I can't remember the last time I saw Claude or ChatGPT confidently answer a question that they should have searched for instead.
If you watch their reasoning traces they often say things like "this is a well-known historical fact so I don't need to search for it", or more frequently they spit off a bunch of searches.
I had an issue with Claude Sonnet the other day in one specific chat where it made shit up without searching, I called it out, and then it searched, got the answer half right, and made up some more shit. It kept doing this several times in the same chat. Didn't have any issues with any other chats, though.
Anecdotally, it still happens a ton to me. They also still make super simple logic errors that they immediately reverse when pressed. For example, I asked Opus 4.7 last night how to cool off my room without making it too humid inside (indoor temp 78°F, humidity 45%; outdoor temp 64°F, humidity 99%). It suggested opening a window and assured me that the humidity would not rise above around 60% which would still be comfortable. I asked it to justify that and it said:
>You're absolutely right about the humidity — I was sloppy with that aside. If you ventilate enough to meaningfully cool the room, you're replacing indoor air with outdoor air wholesale, and you'd converge on outdoor conditions: 64°F and near-100% RH. That's miserable. The 55-60% figure I tossed out was hand-wavy nonsense — it would only hold if you barely cracked the window and mixed a tiny fraction of outdoor air in. At any ventilation rate that actually cools, you're just moving outside air inside.