We'll be keeping our eye on how rapidly CharityChex, a credit card technology that allows customers to make charitable donations when they pay their bill, catches on in the restaurant industry. It's a clever idea, but one that could turn out to be a double-edged sword.

Full-service operators are typically inundated with nonstop requests for donations, and CharityChex finesses that issue in a couple of ways. One is that a requesting charity can be temporarily added to the list of giving options included on each customer's bill. A second is that the funds to support the charity come from the customer, not from the restaurant.

On the other hand, many customers may not appreciate being hit up for a donation this way. Some may assume the restaurant gets a percentage of any donation as a processing fee (CharityChex does; restaurants don't).

Also, we're thinking waitstaffers might see the CharityChex system as a detriment to big tips from satisfied customers, who may choose to split their largesse with a charity. And it's a too-welcome option for those who had a less-than-ideal dining experience, who may opt to give the whole tip to charity to demonstrate their disfavor.

In fact, this latter approach is the business model for an outfit called TurtleTip.com. The company sells stickers poorly served patrons can affix to their bill come payment time. The sticker informs the server that all or part of the tip the customer would normally give for good service will instead be given to charity. Actual giving takes place later via TurtleTip's website.

Both approaches empower restaurant customers. But we have to ask: Considering the staff tension and turnover they might create, who wants to be the front of the house manager where CharityChex is installed or where TurtleTip participants are frequent patrons?