Why you shouldn't refuse to review articles for Elsevier

A fair number of people refuse to review for certain journals, based on their pro or anti open-access stance.

Won't publish, won't referee, won't do editorial work

As Elsevier tells us, that's fine.

Are there any consequences of refusing to review?

Refusal gets the message to the editors, but the authors are the people that prop up the journal (assuming reviewers will always be found somewhere). So it seems better to accept the invitation to review and to include a comment to the authors along the lines of:

We note that you have chosen to submit your article to {JOURNALTITLE}. Have you considered alternatives, such as {JOURNALTITLE} and {JOURNALTITLE}? These journals are preferable because ...

At the very least it'll keep the editors on their toes. If the message reaches the authors, it could be powerful. Targeted, from a place of authority, and hitting a captive audience. You might raise a few hackles, but that's why reviewers get anonymity ;)