If SQL doesn't parse, there are no adverse effects in any way, at least on Oracle, MySQL, Sybase, SQL*Server, or PostgreSQL. I've never used other RDBMSes, so I can't say for sure, but I'd be shocked if there were.

If you're worried about reporting the issue up the chain, the consumer of your DBI wrapper generally doesn't care why something failed, just that it failed at all. I've found it best to just do the whole thing as one big prepare-execute(-fetch) black box and roll errors up from any of the parts.