More obstruction

[mick]

Andy,
Seems to me that we have to look at the type and timing of contact.

Did R1 step on F4?

Did R1 make any effort to avoid F4?

Did F4 attempt to get up and tripped R1?

Was F4 still sprawling from momentum and contacted F4?

Then we get to judge interference, obstruction, train wreck.

Of course, if F4 obstructs and then R1 somehow interferes, then we only call the interference.
mick