No one in FAA land has everu questioned it either.
If you ever do a licence or rating in the USA (maybe you have?) it is the examiners job to check your logbook and sign the 8710 form stating what you have put on there is correct. If you have 1500+ of X/C time, a cursory glance at the logbook by the examiner would verify this and I'm sure he'd be happy with it without taking too much interest in it.
The 8710 form is useful if you ever loose your logbook, the last submitted form can be used as 100%
evidence of your flight time.