I'm a fairly recent member of a real world activism group that often gets called a honeypot, and I can assure you it isn't. There's no real way anyone can prove a group isn't a honeypot, and it only serves to scare people away (as I once was) based on rumours.
There's an easy way to deal with it though: Don't be pushed into doing anything illegal, and don't trust people without getting to know them, and them earning your trust. I'm willing to bet a lot that all of the people in my region are legit, and I have no reason to suspect anyone else either.
Stickering, flyering, leafletting (and talking to people), and banner drops are all low risk activities, though some may be in a legal grey area or straight up illegal. Stickers in particular are a really cheap and easy way to get into the newspapers. Check your local laws (and how likely they are to be enforced) on flyposting and hatespeech, and ensure you stay on the right side of the law e.g. being pro white rather than hateful of non-whites, and implying rather than stating explicitly. If you have flyposting laws I suppose it might be technically possible that you could be punished for it, check what's likely and make sure you're comfortable with it. A cap and sunglasses can go a long way towards hiding your identity without looking weird. Hoodie, scarf, face covering, gloves, are other ways you can take it further if you're worried.
At larger demonstrations you can expect to have run ins with police, maybe even get arrested, but as long as you don't do anything stupid, you won't get charged. In a lot of countries you can be compensated for wrongful arrest, so if the unfortunate happens, make sure to stick it to them so they don't try it again any time soon. Make sure to go no comment in interviews, and be familiar with the whole process, what you can ask for if you are put in a cell, etc. It's easy to be in the wrong place at the wrong time and be arrested at these events, even if you didn't actually do anything.
If you have hatespeech laws, your speakers might be arrested often, so be careful what you say. The people who have been in the group longest and are turning up to demonstrations the most are also the ones putting themselves at risk and volunteering to speak the most, and often getting arrested themselves. It makes me highly doubt any of them are infiltrators, unless the authorities are spending massive resources on us, and are hugely coordinated, and for what? They don't need to infiltrate, they can simply arrest you to get your identities, and you're probably on a list already.
If you have any questions, ask away.
