This question already has an answer here:
Every time I visit this site I notice some questions related to autographs and signatures in general.
In Revisiting autograph identification questions (conclusion: off-topic) it was discussed and the decision that was made is:
CONCLUSION: As the Sports Stack Exchange moderation team, we feel there is sufficient consensus here, both among the community and the moderation team themselves, to declare autograph identification questions off-topic. Thanks to everyone who contributed to the discussion, and to those people who have put effort into answering these questions in the past.
So they are off topic now and as so they are closed.
However, the stream of question keep coming and I suppose it is a bit discouraging for OPs to see it.
For this, I ask: would it be possible to have a warning in place when the Ask Question page detects 'signature' or 'autograph' either in the title or the body of the question?
Note that autograph identification questions are not allowed on this site. Still, you can check What topics can I ask about here? to see how you can contribute when asking a new question.
The Stack Exchange engine allows such warning to be used, or even blocking (see example).