Should file.access(as.character(NA)) return -1 (now 0)?

Should file.access(as.character(NA)) return -1 to be consisting with
non-existing files?

file.access(c("Non-existing-file", NA), mode=1)

Non-existing-file              <NA>
               -1                 0

file.access(c("Non-existing-file", NA), mode=2)

Non-existing-file              <NA>
               -1                 0

file.access(c("Non-existing-file", NA), mode=4)

Non-existing-file              <NA>
               -1                 0

/Henrik

sessionInfo()

R version 2.10.1 Patched (2009-12-24 r50837)
i386-pc-mingw32

locale:
[1] LC_COLLATE=English_United States.1252
[2] LC_CTYPE=English_United States.1252
[3] LC_MONETARY=English_United States.1252
[4] LC_NUMERIC=C
[5] LC_TIME=English_United States.1252

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base