The most likely reason -- especially given the network involvement -- is TOCTTOU.

With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.

RIP Neil Armstrong

In reply to Re^3: Spurious "Invalid Argument" on file open by BrowserUk
in thread Spurious "Invalid Argument" on file open by rovf

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