推荐信寄送必须由推荐人寄还给申请人吗？

请教一下：

看到Haas的推荐表上写道：推荐信要由由推荐人寄还给申请人，然后申请人同一寄到学校。“Ask your recommender to enclose the completed form, seal the envelope, sign across the seal, and mail the envelope back to you. You should then send the envelope with its seal unbroken to the MBA program with the rest of your application materials.”

但是通常推荐信就直接从推荐人那里取回来了所以不用邮寄的，或者用快递寄所以看不到信封上的邮戳的。这样会不会有问题啊？