Now that oil is back up to $70 a barrel, are surcharges back, too?

Cruise blogger Gene Sloan at USA Today, who's always on top of the latest developments in the tricky world of the cruise ship biz, was quick to tweet a warning to consumers after Tuesday's closing bell on Wall Street. The price of a barrel of oil had just closed over $70 for the first time since last fall.

Sloan pointed out that most of the major cruise lines post specific verbiage on their Web sites that gives them latitude to start charging more for fuel should oil go above $70.

Here's Carnival's wording, listed online: "The company reserves the right to re-instate the fuel supplement for all guests at up to $9 per person per day if the NYMEX oil price exceeds $70 per barrel."

Royal Caribbean's threshold is even lower: "We reserve the right to reinstate fuel supplement charges if the price of West Texas Intermediate fuel exceeds $65 per barrel..."