Identifiers beginning with a character of type Nd, Mc, or Me should be forbidden. This is an R6RS issue.
Programmers shouldn't expect a number like ١٢٣٤ (1234 in Arabic digits) to work as an identifier.
Combining marks at the beginning of an identifier would combine with the previous ( or whitespace or what not, which would be extremely confusing.
The WG voted to adopt this proposal.