[dngray]

What I am curious to know is what stops someone using this to get around spam filtering.

Ie send something that gets through the spam filter then change it later.

Also on another note I'm pretty sure google marks your emails as spam if you say things like "getting off gmail" or "switching provider".

I have been sending emails to my mother for ages from my own domain (and email server), none of them have ever been marked as spam. One day I sent her an email about switching provider with a mention of some of the good ones on privacytools.io.

That email remarkably got marked as spam. It is a good thing she checks her spam box, but now I think I have all the evidence I need to get her to switch. Also, none of the subsequent emails I ever sent her got marked as spam.

[massaman_yams]

That message going to spam is almost certainly an issue with the domain reputation of one or more of the URLs you included.

Easy to test, really. Send her a new message with the same text as before, but without any URLs.