slapd(8) can handle those occurrences. slapadd(8) is intended to load LDIF files generated by slapcat(8), thus presumably consistent. In general, it deals with the most obvious errors. I don't think asking slapadd to perform these checks is a good idea, as it would slow it down without real benefit: if an error is caught, you would need to restart, wasting all the actual write effort. A sanity check tool for unreliable LDIF would probably be more appropriate.
p.
