My personal feeling is that's not their decision to make. OO is not the be-all, end-all. Using OO for the sake of it when it is not warranted is silly.

The technical details of the implementation are up to you as the programmer. Use the right tool. If OO makes sense for the script, use it. Do what is simplest, and most maintainable, and makes sense for the application.

I get into this at work all the time, where management wants to dictate a piece of the technology, where they are not knowledgeable. It needs to be left up to us, the programmers, to make the proper technical design decisions (within reason of course, that doesn't mean telling the company to switch from Linux to FreeBSD just because prefer it or whatever... there needs to be merit.)