In newer versions of the seam/wicket integration, the wicket filter will only activate contexts when a request is received that wicket handles. This is in the seam trunk, which you could build yourself, or grab a nightly build. It will be in the next release of Seam, 2.1.2CR1.
Alternatively, use a <web:wicketFilter> declaration in your components.xml to restrict the wicketFilter to ignore your web service paths (with regex-url-pattern), if the web services have paths that lend themselves to pattern-based exclusion.
Thanks, I'll grep myself a 2.1.2-SNAPSHOT
Any thoughts on when to expect a normal 2.1.2 version ?
Don't know, a schedule hasn't been announced, AFAIK.