A negative freeroll is relatively common in low stakes amateur play, but in higher stakes play, it is considered a serious blunder to  allow a negative freeroll on the final round of betting due to the amount of risk involved.
A detrimental freeroll is relatively common in low-stakes amateur games, but in higher-stakes games, it is considered a severe error to permit a negative freeroll on the final round of betting due to the substantial risk involved.