1. See the detailed analysis at Calliess, Nach der Schuldrechtsreform: Perspektiven des Verbrauchervertragsrechts, Archiv für die Civilistische Praxis (AcP) 203 (2003), forthcoming.
2. An exception may be a characteristic performance, which usually can be used for private use only, or a contract, where the volume or value usually is only demanded by businesses: see Ferrari, in: Schlechtriem (ed.), CISG-Kommentar, 3rd ed. 2000, Art 2 N. 17 f.; However, the majority of all products and services can be used for private and/or professional use. Thus, there should be a clear distinction in advance, based on the external circumstances or the representations of the parties.
3. See Ferrari, in: Schlechtriem (ed.), CISG-Kommentar, 3rd ed. 2000, Art 2 N. 15 ff.
4. See Grundmann, Europäisches Verbrauchervertragsrecht im Spiegel der ökonomischen Theorie – Vertragsinformationsrecht im Binnenmarkt, in: Ott/Schäfer (ed.), Vereinheitlichung und Diversität des Zivilrechts in transnationalen Wirtschaftsräumen, 2002, 284 ff.
5. In the Isle-of-Man Case decided by the FCJ (BGHZ 135, 124), for instance, the lower Courts had not even tried to solve the case under the laws of the Isle-of-Man. The whole argument was just about the applicability of the German protection rules. Thus, the FCJ in its decission simply presumed, that the contract would be enforceable under the law of the Isle-of-Man (at II 2 and 3).