The question isn't "how reliable", but rather "how reliant". In other words, how much does aikido rely on committed attacks to be effective? If an aikidoka is not given a committed attack, can he still execute effective aikido?

(Edit to add, as I'm trying to study German: be reliable = verlässlich sein, zuverlässig sein; be reliant on = angewiesen sein auf, abhängig sein von. Ich hoffe, das hilft! )