Although there's no specific requirement for them, a bike must meet this requirement:
"(b) assistance shall be cut off when the cyclist stops pedalling forward such that the cut off distance does not exceed 5 m with the use of brake lever cut off switch or 2 m without the use of brake lever cut off switch. This requirement has to be checked according to the test methods described in 4.2.4.2.2 b);"
and this one:
"The electrical control system shall be designed so that, should it malfunction in a hazardous manner, it shall switch off power to the electric motor."
If the bike has a PAS sensor, it won't cut the power off fast enough. If the bike only has a throttle, then you're out on this one:
"(a) assistance shall be provided only when the cyclist pedals forward. This requirement has to be checked according to the test methods described in 4.2.4.2.2 a);"
In summary, you have to have brake cut offs with all bikes that don't have a fast response torque sensor until someone comes up with a faster responding PAS.