Venue with plug and play sound system?

Hi

I saw a venue today that has a plug and play sound system and requires no equipment from the DJ. They said sometimes they will have them bring in a sub but other than that they state in the contract that no other equipment can be brought in. I'll have to find what they have in there but I figured most dj's would prefer their own equipment. Any dj have any experience with a venue like this and what would you need to know exactly to determine if you can use theirs? I'm not sure what things I should be asking there. Thanks!