Substitution play

[Robert Goodman]

Originally Posted by Berkut

I really don't understand why there is always a question about whether plays of this type are legal.

There's no reason to ask in advance, because you know what your own intention is when you're planning it, and so does anyone else if you ask them about it. However, there is sometimes reason to ask after you've seen it done by someone else, "Was that legal?", because you may not know whether they were attempting to feign a substitution.