Not Inland Revenue as such, but...
The DWP "interviewed" my sister for falsely claiming Disability Living Allowance, despite having a child with Downs Syndrome. Turns out she had marginally overclaimed, but largely because the DWP had obfuscated the procedure for advising them when she moved house (which she did do, but just not the way they wanted). Having agreed a reasonable timescale for paying back the overpayment like any reasonable person would she was then sued for fraud.
Moral of the story? If the Government offer you money for any reason whatsoever, check and double check that they have got their figures right.