This is very common and easily accomplished without scamming and putting your credit & status at risk.

Call the hotel (not the 800#) and explain what you want. They will email you a form which you can complete and fax back. It will contain the CC info. and your personal guarantee of all charges as you specify. Generally you can choose to pay for just room & tax or you can choose to pay for all charges. In the former situation, your guests will be asked to provide a CC to cover the cost of incidentals.

But, be forewarned. You are accepting personal liability for everything. Lots of bad threads here about people who did this for others they don't know particularly well. Their "guests" damaged, trashed, smoked in or otherwise incurred significant costs and there was insufficient credit on the CC to cover the damages. Those get charged back to you. (Think drunk guest who totals another's vehicle in the parking lot, etc).

Even when it's close friends -- a great way to end a friendship. "We thought that you would order a normal dinner, didn't think you'd order lobster via room service every night...."