Look at the publication. If they have been around, as Martin said, and are a legitimate, established, business then you maybe want to take the chance. If they publish photos all the time that means there are plenty of photogs willing to work under their terms.
I doubt that any legitimate company in the publishing business is going to use your image and not pay you. Maybe some sleazy out fit would, but not a legitimate one.
The thing is, if you are not an established, high demand photographer, you may have to take some chances. When you are selling and making all the money you want to make you can make more demands. If you are trying to grow your business, then a little more risk taking may be in order.
The market place is overwhelmed with great images. I know great photographers that send CD roms full of high resolution images to publications like Westways Magazine, National Geographic and others, just hoping to get one of their images published. Some of them have been very successful at doing that. Others not so much. Some get paid and some do it just so they can say they were published in National Geographic or some other high profile publication. The bottom line is it's a buyers market unless you are a high demand talent.
Everyone's situation is different. You have to decide what is right for you. I would also keep in mind that sending them a file is NOT a hard money loss if they have the file and you do not get paid.
And remember, the possibility that they will deviate from their terms will be directly related to how bad they want YOUR photo.
EDITED: Marlene has the right attitude, imho. You have to take chances if you are going to be successful in any business. The art business is no different.