Identify the unfair aspect with respect to the sentence extracted from an online Terms of Service:
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except for such updated terms , this agreement may not be modified except by mutual written agreement between you and linden lab that is signed by hand ( not electronically ) by duly authorized representatives of both parties and expressly references amendment of this agreement . 

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. OPTIONS: ["Unilateral change", "Unilateral termination", "Limitation of liability", "Content removal", "None", "Arbitration", "Choice of law", "Contract by using", "Jurisdiction"].