To figure out what restrictions may exist in your area, you could try asking other local members of your area by placing a post in a local discussion or contacting a local Ambassador. Active members of the community who have been hosting in your area may be able to offer some feedback on this. Alternatively, you can always ask the local authorities directly for their advice on this.
Registering a Guest - Asking for Identification
In some countries local legislation dictates that a host should register their guest at their local police station, letting them know about the duration of the stay, etc. In other countries there's no such restrictions. You should try to find out what restrictions, if any, apply in your country and your area.
On another note, some hosts may ask to see a photocopy of their guest's identification (ID card or passport) upon arrival. Some even set it as a requirement in order to host. This is not a requirement for hosting set by Couchsurfing, but it's also not against any rule for hosts to make that request. After all, they open their home to somebody they haven't met before, and this can be seen as an act of mutual trust between the two people.
So, it's up to you if you ask to see some form of ID and also up to the guest to accept to show it, or move on to another host.