It doesn’t change the intended meaning but it can change the interpreted one.
For example when I write “I love to give my data to Google /s” you can be sure that I actually do not love to give my data to Google, whereas leaving out the ‘/s’ I could have meant it sincerely (for example, because I want targeted ads, perfectly tailored to my needs).
This example clearly illustrates the totally opposite interpreted meaning.
But in the case of the comment we are discussing, disclosing the sarcasm makes no difference to either side of the conversation (the sender and the readers)
It doesn’t change the intended meaning but it can change the interpreted one.
For example when I write “I love to give my data to Google /s” you can be sure that I actually do not love to give my data to Google, whereas leaving out the ‘/s’ I could have meant it sincerely (for example, because I want targeted ads, perfectly tailored to my needs).
This example clearly illustrates the totally opposite interpreted meaning.
But in the case of the comment we are discussing, disclosing the sarcasm makes no difference to either side of the conversation (the sender and the readers)