I am one of those people who let others use my stuff with credit (unless otherwise specified -- some of my stuff is completely public domain) but it's important to note that not everyone is like that.
I once saw a user (whos name will be redacted for privacy) who made a scene and in the description said that others cannot use it, even with credit -- and that's completely okay. It's important to respect these boundaries.
You may have confused this scene with another -- I haven't put any NumberBlocks in this scene (I'm not even entirely sure what NumberBlocks is... I know it's a TV show but that's about it)
QUOTE: BUT, even with a statement like that there still could be an issue if YOU copied someone else's work without permission and then another person copied the thing that you copied! That actually happens a lot here on Algobox!
I try not to use other's work in my scenes -- and in the rare cases I do, I ask for permission first.