Player takes unsigned scorecard | Golf Monthly

indeed - note the different wordings and instructions

"a. Recording Scores

After each hole the marker should check the score with the competitor and record it. On completion of the round the marker must sign the score card and hand it to the competitor. If more than one marker records the scores, each must sign for the part for which he is responsible.
b. Signing and Returning Score Card

After completion of the round, the competitor should check his score for each hole and settle any doubtful points with the Committee. He must ensure that the marker or markers have signed the score card, sign the score card himself and return it to the Committee as soon as possible. "

As to the OP, there would have to be a reasonable assumption available that your card was going to be returned to you prior to your returning it to the committee. On the wording above I can't see that at all. The only other question would be the definition of the scoring area by your committee (they have to define it) and if you hadn't left that area then you are able to sign the card. Most define it rather tightly but some have it quite wide to avoid many such situations.