Answer: the coin flipper was not cheating.
Step-by-step explanation: the observed frequency has some degree of accuracy than the expected frequency, therefore the discrepancy in value.
The expected frequency was not definite, it was just a mere expectation from reasoning of what frequency is, so any result it gives cannot be considered to be accurate.
The observed frequency was gotten by careful experimental procedure following the true laid down definition of frequency, hence has some degree of accuracy than the expected frequency.