Even being polite is not guaranteed to have them thinking nicely about you, but we do our best. I did do my best recently with an approach. Repeatedly.
I had a previous employer back in the UK trying to get me on a list for a temp job. They do special contracts, treat you as self-employed. You need special police checks for it (youth and adult workforce) and must have a verifiable background and understand the work environment (having grown up in it/worked in it), have specific education/training and experience.
Anyhow, I tried to politely tell the first contact that I would be unavailable (as on another continent) This went back and forth, then the HR manager got on to me and their written “voice” was quite snotty. There was no way I was coming back for 4-5 month’s work, giving up my relatively stable job, during times of covid where I would be unable to return to my job (country I’m in isn’t going to let me back in). Any other time, I “may” have been interested. I’m not taking it personally though.