Currently, the Skype buttons used in profiles are linked to use the call action (skype:echo123?call), and even though Skype pops up with a confirmation message, it still has the potential for some unexpected calls - particularly if users have their privacy settings in Skype set to recieve calls from anyone.
If possible, I think it would be a better alternative to change these links to use the userinfo action (skype:echo123?userinfo)
This action leads to a Skype popup of the user's profile that allows for people add them as a contact, which in most cases is the reason people click these buttons in the first place.
An added benefit to this is that they can double check the information in the profile so they can be sure they're adding the right person.