False positives for pass-by-reference parameters

Thanks for reporting this. :)
Fixed and committed: http://drupalcode.org/project/drupalcs.git/commit/f6555d5

Are we sure about that? I think it is a huge advantage if I see in the documentation that the parameter is taken as reference. Do we have any rule regarding this in the coding standards?

Klausi you're right - at least I couldn't find such a rule.
We should try to get such a rule into the standards and then adjust the sniff accordingly.
According to the documentation we should:

Note: Before making any changes to the standards in this document, please file an issue in the Drupal issue queue, with component "documentation", so your proposed changes can be discussed.

Shall we open such an issue or does anyone know who we could contact first?

I have disabled the warning if the "&" is in the @param documentation until this is sorted out. See http://drupalcode.org/project/drupalcs.git/commit/1a6268a

I would say this issue stays "active" until we have a drupal core issue to settle the coding standards for this.

Opened a core issue: #1368794: Using '&' in doxygen @param documentation. This issue is postponed until we reach a solution there.

Drupal Code Sniffer has been merged into Coder 7.x-2.x. Please move this issue to the Coder queue and reopen it if the problem still exists.