let's do a simple experiment.

pair up raichu and pika as i mentioned above. (of course u can use any pokemon. just an eg here.)

try to get a wild pika. feed it one HONDEW. It will say that sp att cannot fall anymore.
get raichu to KO a slugma. feed HONDEW to pika this time. Now it will say that sp att fell.

Conclusion: Pika gained an EV without battling.
The HONDEWs do not lie...

Wat was ur method of "checking several times", vanirelf?