Etiquette - How NOT to ask for cash

Cash is obviously an appreciated wedding present, but is there any way to tactfully for it?A friend told me yesterday that her friend has increasingly seen "No boxed gifts" on wedding invitations. Her friend said that this is because a lot of people are paying for their own weddings and want cash. Interestingly enough, this friend was a doctor so I wonder if it was recently minted doctors hurting from their school loans.

Anyway, that message instantly illicited a gasp from the people that overheard. This is NOT a good way to ask for cash. Enclosing registry information in the invitations is already pushing it. But printing a line in your invite that asks for gifts, but not "boxed" ones is not tactful. Everyone who heard this story said they would be turned off from giving a gift at all. In this day and age, many people (especially couples over age 25) tend to pay for their own weddings so this is not a good reason.

While expenses are certainly high for any wedding (especially when one want to include awesome things like photobooths and chocolate fountains, etc.), and especially hurts when a couple is paying for their wedding, gifts are traditionally given for a bride's shower ("showering with gifts"), and not the wedding itself. Of course most wedding attendees will give gifts now. Some may just give cash anyway.

It is a tough question to answer, but explanations may be a good start. For example, a friend said to me "We are moving and there is not much space to store things at his parent's place." I understood and gave her a nice frame and cash. Another friend didn't even have a registry (which leaves the door open for strange gifts), but since I knew she was also renovating her house, I gave her cash too. I frequently give cash and a gift because I try to give them a gift they would use and I know they would appreciate cash.

Any thoughts on how else one can tactfully ask for cash, if attendees insist on giving gifts?