It can be hard to know who you should invite on a stag or hen weekend. This is especially true because of the fact that the guest list usually falls to the best man or head bridesmaid, meaning that one person has to think of another person's ideal guest list for their stag/hen celebrations.
Working out who you will invite is one thing, but working out who to leave out is almost a separate process and just as difficult. It also involves some of the most difficult decisions, as leaving people out carries the risk of causing offence. However, even if it's difficult, the following are people you may want to consider cutting from the invite list.
Parents
Some people laugh at the very idea of inviting parent on a bachelor/ette weekend. Others think that it's only natural, since the party is all about the bride or groom's nearest and dearest. When the stag/hen and the person planning the guest list fall into separate camps, the results can be awkward.
Think carefully about what the bride or groom's personal viewpoint is likely to be on the matter, as well as about the type of celebrations that will be enjoyed and the personality of the parent in question. This will help you decide whether a parent will be a welcome addition to the party or an awkward one. The type of celebration may well be the most important point. Parents are more likely to be welcome at a dinner or evening of quiet drinks than on a club crawl.
People who won't be invited to the wedding
Some people take the view that the pre-wedding celebrations should be a more inclusive affair, and invite along people who aren't necessarily invited to the wedding ceremony or to the reception. While this is nice in principle, it can lead to awkward misunderstandings.
Another common group of thought is that the stag or hen weekend is for the very closest friends, who will naturally be invited to the wedding. This can lead to people assuming they are welcome to attend the ceremony, or feeling awkward and left-out because they don't have an invite.
The bride/groom's exes
It isn't necessary to cut anyone who has ever had a relationship with the soon-to-be-wed guy or gal off the guest list, but careful consideration is needed. Inviting exes can potentially be very awkward for the stag or hen, or for their current partner.
For many heterosexual couples, this won't be an issue as the party will often be a single-gender affair. For same-sex couples or those enjoying mixed celebrations, this can be a source of real consternation. If the bride- or groom-to-be is still good friends with an ex, and there is no awkwardness between the two or between ex and current partner, then everything is fine. If they are on civil terms with the stag/hen at best and you are mostly considering inviting them because all their friends are invited, it is probably wise to leave them off the list.