помогите с предлогом busin.

[Daffodil3]

Подскажите пож-та как какой предлог использовать на отрезке "unforeseen and extraordinary events ......... potential training participants": в след. предложении:
Even worse, there are times when planned training sessions are cancelled because of unforeseen and extraordinary events ??????? potential training participants.

Оригинал:
Хуже того, иногда отменяются уже запланированные и организованные тренинги из-за неожиданных и чрезвычайных обязательств потенциальных участников тренинга.

ЗС

[naturalblue]

when would-be trainees are faced with some contingencies?

[sledopyt]

rephrase:
... when scheduled training sessions are canceled following/[as a result of] cancellations (received) from registered participants due to unforeseen ...

[123:]

contingent and extraordinary liabilities of the potential trainees

[felog]

consider:
consider:
Or even worse when training classes/courses/sessions that are on schedule and about to start are cancelled due/owing to unexpected/unforeseen and emergency circumstances/ contingencies/developments/situations

[Baxter]

IMHO
owing to force majeure circumstances