Trapping a park

I had this in a different thread but need a few opinions.

I won a bid for the city to do gopher removal at a soccer field next to a playground. The field is used daily and never closed. I will be using albano traps

My options are:

1. Close the whole field for two 10 day periods while I trap. There would be signs from the county stating "Field Maintenance in Progress" with no hint to trapping

2. Do half the field at a time, closing the other half.

3. Tape of the area surrounding the mounds leaving the rest of the field open.

4. Close nothing and leave the entire park open and no indication of anything going on.

I like #4 but have no idea if that's even feasible. Soccer is a pretty big sport in our state ( My son P.J. was a state champ ) but

there would be plenty of opportunities to set up traps when the fields are empty. Especially on school days. Are the gophers right in

the middle of the soccer fields? I guess if that's the case, the fields would have to be closed.

I plan on setting at night to avoid anyone seeing me.

It is lightly used, no official games there, just casual frisbee games and a few people with kick the ball around. The damage isn't horrendous, but there are some mounds in the field, and quite a few in the edges. Would my traps really pose a bigger threat than the mounds?